diff --git a/app/Console/Commands/BackfillMessageAttachments.php b/app/Console/Commands/BackfillMessageAttachments.php
new file mode 100644
index 000000000..4ec4eb4ca
--- /dev/null
+++ b/app/Console/Commands/BackfillMessageAttachments.php
@@ -0,0 +1,131 @@
+<?php
+
+namespace App\Console\Commands;
+
+use App\Models\WebSocketDialogMsg;
+use App\Models\WebSocketDialogMsgAttachmentBackfill;
+use App\Module\Base;
+use App\Services\MessageAttachmentBackfillService;
+use App\Services\MessageAttachmentService;
+use Illuminate\Console\Command;
+
+class BackfillMessageAttachments extends Command
+{
+    protected $signature = 'collaboration-files:backfill-attachments
+        {--after=0 : 从此消息ID之后开始}
+        {--before=0 : 处理到此消息ID，默认取启动时的最大ID}
+        {--batch=500 : 每批处理消息数量}
+        {--limit=0 : 本次最多处理消息数量，0表示不限}
+        {--sleep=0 : 每批结束后的休眠毫秒数}
+        {--status : 查看自动回填状态，不处理消息}
+        {--dry-run : 只解析和统计，不写入附件表}';
+
+    protected $description = '分批回填协作文件所需的消息附件索引';
+
+    public function handle(): int
+    {
+        if ($this->option('status')) {
+            return $this->showStatus();
+        }
+
+        $after = max(0, intval($this->option('after')));
+        $before = max(0, intval($this->option('before')));
+        $batch = min(2000, max(1, intval($this->option('batch'))));
+        $limit = max(0, intval($this->option('limit')));
+        $sleep = min(60000, max(0, intval($this->option('sleep'))));
+        $dryRun = boolval($this->option('dry-run'));
+
+        if ($before === 0) {
+            $before = intval(WebSocketDialogMsg::withTrashed()->max('id'));
+        }
+        if ($before <= $after) {
+            $this->info("没有需要处理的消息（after={$after}, before={$before}）");
+            return self::SUCCESS;
+        }
+
+        $this->info(sprintf(
+            '开始回填消息附件：范围 (%d, %d]，批量 %d%s',
+            $after,
+            $before,
+            $batch,
+            $dryRun ? '，仅预览' : ''
+        ));
+
+        $lastId = $after;
+        $processed = 0;
+        $attachmentCount = 0;
+        $emptyCount = 0;
+        $failedIds = [];
+
+        while ($lastId < $before && ($limit === 0 || $processed < $limit)) {
+            $take = $limit > 0 ? min($batch, $limit - $processed) : $batch;
+            $messages = MessageAttachmentBackfillService::candidateQuery($lastId, $before)
+                ->take($take)
+                ->get();
+
+            if ($messages->isEmpty()) {
+                break;
+            }
+
+            foreach ($messages as $message) {
+                $lastId = intval($message->id);
+                $processed++;
+                try {
+                    if ($dryRun) {
+                        $data = Base::json2array($message->getRawOriginal('msg'));
+                        $count = count(MessageAttachmentService::extract((string)$message->type, $data));
+                    } else {
+                        $count = MessageAttachmentService::sync($message);
+                    }
+                    $attachmentCount += $count;
+                    if ($count === 0) {
+                        $emptyCount++;
+                    }
+                } catch (\Throwable $e) {
+                    $failedIds[] = $lastId;
+                    $this->warn("消息 {$lastId} 处理失败：{$e->getMessage()}");
+                }
+            }
+
+            $this->line("已处理 {$processed} 条消息，附件 {$attachmentCount} 条，当前消息ID {$lastId}");
+            if ($sleep > 0 && $lastId < $before) {
+                usleep($sleep * 1000);
+            }
+        }
+
+        $this->newLine();
+        $this->info("回填结束：消息 {$processed} 条，附件 {$attachmentCount} 条，无有效附件 {$emptyCount} 条");
+        $this->info("续跑参数：--after={$lastId} --before={$before}");
+        if (!empty($failedIds)) {
+            $this->error('失败消息ID：' . implode(',', $failedIds));
+            return self::FAILURE;
+        }
+
+        return self::SUCCESS;
+    }
+
+    private function showStatus(): int
+    {
+        $state = WebSocketDialogMsgAttachmentBackfill::query()->orderBy('id')->first();
+        if (!$state) {
+            $this->warn('自动回填任务尚未登记，请先执行数据库迁移');
+            return self::FAILURE;
+        }
+
+        $this->table(['项目', '值'], [
+            ['状态', $state->status],
+            ['消息快照上界', $state->before_msg_id],
+            ['当前消息ID', $state->last_msg_id],
+            ['成功处理消息', $state->processed_count],
+            ['已索引附件', $state->attachment_count],
+            ['无有效附件消息', $state->empty_count],
+            ['失败尝试', $state->failure_count],
+            ['当前连续重试', $state->retry_count],
+            ['下次重试时间', $state->next_retry_at?->toDateTimeString() ?: '-'],
+            ['最近错误', $state->last_error ?: '-'],
+            ['首次开始时间', $state->started_at?->toDateTimeString() ?: '-'],
+            ['完成时间', $state->completed_at?->toDateTimeString() ?: '-'],
+        ]);
+        return self::SUCCESS;
+    }
+}
diff --git a/app/Http/Controllers/IndexController.php b/app/Http/Controllers/IndexController.php
index d08bd1671..0d015095c 100755
--- a/app/Http/Controllers/IndexController.php
+++ b/app/Http/Controllers/IndexController.php
@@ -25,6 +25,7 @@ use App\Tasks\ManticoreSyncTask;
 use App\Tasks\UnclaimedTaskRemindTask;
 use App\Tasks\TodoRemindTask;
 use App\Tasks\AiTaskLoopTask;
+use App\Tasks\MessageAttachmentBackfillTask;
 use Hhxsv5\LaravelS\Swoole\Task\Task;
 use App\Module\PatchedAvatar as Avatar;
 
@@ -281,6 +282,8 @@ class IndexController extends InvokeController
         Task::deliver(new ManticoreSyncTask());
         // AI 任务建议
         Task::deliver(new AiTaskLoopTask());
+        // 聊天附件历史索引回填
+        Task::deliver(new MessageAttachmentBackfillTask());
 
         return "success";
     }
diff --git a/app/Models/WebSocketDialogMsg.php b/app/Models/WebSocketDialogMsg.php
index 909c2c224..99950a821 100644
--- a/app/Models/WebSocketDialogMsg.php
+++ b/app/Models/WebSocketDialogMsg.php
@@ -11,6 +11,7 @@ use App\Tasks\PushTask;
 use App\Models\ProjectTaskRelation;
 use App\Exceptions\ApiException;
 use App\Tasks\WebSocketDialogMsgTask;
+use App\Services\MessageAttachmentService;
 use Hhxsv5\LaravelS\Swoole\Task\Task;
 use Illuminate\Database\Eloquent\SoftDeletes;
 
@@ -1477,6 +1478,7 @@ class WebSocketDialogMsg extends AbstractModel
             ];
             $dialogMsg->updateInstance($updateData);
             $dialogMsg->generateKeyAndSave($search_key);
+            MessageAttachmentService::syncSafely($dialogMsg, true);
             ProjectTaskRelation::recordMentionsFromMessage($dialogMsg);
             //
             WebSocketDialogUser::whereDialogId($dialog->id)->whereUserid($sender)->whereHide(1)->change([
@@ -1544,6 +1546,7 @@ class WebSocketDialogMsg extends AbstractModel
                     'updated_at' => Carbon::now()->toDateTimeString('millisecond'),
                 ]);
             });
+            MessageAttachmentService::syncSafely($dialogMsg);
             ProjectTaskRelation::recordMentionsFromMessage($dialogMsg);
             //
             $task = new WebSocketDialogMsgTask($dialogMsg->id);
diff --git a/app/Models/WebSocketDialogMsgAttachment.php b/app/Models/WebSocketDialogMsgAttachment.php
new file mode 100644
index 000000000..9599f362b
--- /dev/null
+++ b/app/Models/WebSocketDialogMsgAttachment.php
@@ -0,0 +1,49 @@
+<?php
+
+namespace App\Models;
+
+/**
+ * @property int $id
+ * @property int $msg_id 消息ID
+ * @property int $dialog_id 会话ID
+ * @property string $source_type 来源类型
+ * @property string $kind 附件类型
+ * @property int $position 消息内附件顺序
+ * @property string $name 附件名称
+ * @property string $ext 文件扩展名
+ * @property string|null $path 原文件地址
+ * @property string|null $thumb 缩略图地址
+ * @property int $size 文件大小(B)
+ * @property int $width 图片宽度
+ * @property int $height 图片高度
+ * @property \Illuminate\Support\Carbon|null $created_at
+ * @property \Illuminate\Support\Carbon|null $updated_at
+ * @method static \Illuminate\Database\Eloquent\Builder|WebSocketDialogMsgAttachment newModelQuery()
+ * @method static \Illuminate\Database\Eloquent\Builder|WebSocketDialogMsgAttachment newQuery()
+ * @method static \Illuminate\Database\Eloquent\Builder|WebSocketDialogMsgAttachment query()
+ * @method static \Illuminate\Database\Eloquent\Builder|WebSocketDialogMsgAttachment whereMsgId($value)
+ * @mixin \Eloquent
+ */
+class WebSocketDialogMsgAttachment extends AbstractModel
+{
+    public const SOURCE_FILE_MESSAGE = 'file_message';
+    public const SOURCE_INLINE_IMAGE = 'inline_image';
+
+    public const KIND_FILE = 'file';
+    public const KIND_IMAGE = 'image';
+
+    protected $fillable = [
+        'msg_id',
+        'dialog_id',
+        'source_type',
+        'kind',
+        'position',
+        'name',
+        'ext',
+        'path',
+        'thumb',
+        'size',
+        'width',
+        'height',
+    ];
+}
diff --git a/app/Models/WebSocketDialogMsgAttachmentBackfill.php b/app/Models/WebSocketDialogMsgAttachmentBackfill.php
new file mode 100644
index 000000000..6b248f7c1
--- /dev/null
+++ b/app/Models/WebSocketDialogMsgAttachmentBackfill.php
@@ -0,0 +1,52 @@
+<?php
+
+namespace App\Models;
+
+/**
+ * @property int $id
+ * @property string $status
+ * @property int $before_msg_id
+ * @property int $last_msg_id
+ * @property int $processed_count
+ * @property int $attachment_count
+ * @property int $empty_count
+ * @property int $failure_count
+ * @property int $retry_count
+ * @property string|null $last_error
+ * @property \Illuminate\Support\Carbon|null $started_at
+ * @property \Illuminate\Support\Carbon|null $completed_at
+ * @property \Illuminate\Support\Carbon|null $next_retry_at
+ * @property \Illuminate\Support\Carbon|null $created_at
+ * @property \Illuminate\Support\Carbon|null $updated_at
+ * @mixin \Eloquent
+ */
+class WebSocketDialogMsgAttachmentBackfill extends AbstractModel
+{
+    public const STATUS_PENDING = 'pending';
+    public const STATUS_RUNNING = 'running';
+    public const STATUS_FAILED = 'failed';
+    public const STATUS_COMPLETED = 'completed';
+
+    protected $table = 'web_socket_dialog_msg_attachment_backfills';
+
+    protected $fillable = [
+        'status',
+        'before_msg_id',
+        'last_msg_id',
+        'processed_count',
+        'attachment_count',
+        'empty_count',
+        'failure_count',
+        'retry_count',
+        'last_error',
+        'started_at',
+        'completed_at',
+        'next_retry_at',
+    ];
+
+    protected $casts = [
+        'started_at' => 'datetime',
+        'completed_at' => 'datetime',
+        'next_retry_at' => 'datetime',
+    ];
+}
diff --git a/app/Services/MessageAttachmentBackfillService.php b/app/Services/MessageAttachmentBackfillService.php
new file mode 100644
index 000000000..6a8c00615
--- /dev/null
+++ b/app/Services/MessageAttachmentBackfillService.php
@@ -0,0 +1,193 @@
+<?php
+
+namespace App\Services;
+
+use App\Models\WebSocketDialogMsg;
+use App\Models\WebSocketDialogMsgAttachmentBackfill;
+use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Support\Facades\Cache;
+
+class MessageAttachmentBackfillService
+{
+    public const DEFAULT_BATCH_SIZE = 500;
+    public const DEFAULT_TIME_LIMIT = 40;
+
+    private const LOCK_KEY = 'collaboration-files:attachment-backfill';
+    private const LOCK_SECONDS = 120;
+
+    /**
+     * 自动回填与手工回填共用同一套候选消息筛选规则。
+     */
+    public static function candidateQuery(int $after, int $before): Builder
+    {
+        return WebSocketDialogMsg::query()
+            ->where('id', '>', $after)
+            ->where('id', '<=', $before)
+            ->where(function ($query) {
+                $query->where('type', 'file')
+                    ->orWhere(function ($text) {
+                        $text->where('type', 'text')
+                            ->where(function ($images) {
+                                $images->where('msg', 'like', '%browse%')
+                                    ->orWhere('msg', 'like', '%[:IMAGE:browse:%');
+                            });
+                    });
+            })
+            ->orderBy('id');
+    }
+
+    /**
+     * 在时间预算内推进自动回填；已有任务运行时直接跳过。
+     */
+    public static function processAutomatic(
+        int $batchSize = self::DEFAULT_BATCH_SIZE,
+        int $timeLimit = self::DEFAULT_TIME_LIMIT
+    ): array {
+        $batchSize = min(2000, max(1, $batchSize));
+        $timeLimit = min(50, max(1, $timeLimit));
+        $lockKey = config('app.env') . ':' . self::LOCK_KEY;
+        $lock = Cache::store('redis')->lock($lockKey, self::LOCK_SECONDS);
+        if (!$lock->get()) {
+            return ['status' => 'locked'];
+        }
+
+        try {
+            return self::processState($batchSize, $timeLimit);
+        } finally {
+            $lock->release();
+        }
+    }
+
+    private static function processState(int $batchSize, int $timeLimit): array
+    {
+        $state = WebSocketDialogMsgAttachmentBackfill::query()->orderBy('id')->first();
+        if (!$state) {
+            return ['status' => 'missing'];
+        }
+        if ($state->status === WebSocketDialogMsgAttachmentBackfill::STATUS_COMPLETED) {
+            return ['status' => WebSocketDialogMsgAttachmentBackfill::STATUS_COMPLETED];
+        }
+        if ($state->next_retry_at && $state->next_retry_at->isFuture()) {
+            return ['status' => 'waiting'];
+        }
+
+        $before = intval($state->before_msg_id);
+        if (!$state->started_at) {
+            // 迁移到新服务启动之间仍可能由旧进程写入消息，首次运行时补齐这段升级窗口。
+            $before = max($before, intval(WebSocketDialogMsg::withTrashed()->max('id')));
+        }
+
+        $state->update([
+            'status' => WebSocketDialogMsgAttachmentBackfill::STATUS_RUNNING,
+            'before_msg_id' => $before,
+            'started_at' => $state->started_at ?: now(),
+            'next_retry_at' => null,
+        ]);
+
+        $startedAt = microtime(true);
+        $lastId = intval($state->last_msg_id);
+        $processed = intval($state->processed_count);
+        $attachmentCount = intval($state->attachment_count);
+        $emptyCount = intval($state->empty_count);
+
+        while ($lastId < $before && microtime(true) - $startedAt < $timeLimit) {
+            $messages = self::candidateQuery($lastId, $before)
+                ->take($batchSize)
+                ->get();
+
+            if ($messages->isEmpty()) {
+                return self::complete($state, $before, $processed, $attachmentCount, $emptyCount);
+            }
+
+            foreach ($messages as $message) {
+                try {
+                    $count = MessageAttachmentService::sync($message);
+                } catch (\Throwable $e) {
+                    self::fail($state, $lastId, $processed, $attachmentCount, $emptyCount, $e);
+                    return [
+                        'status' => WebSocketDialogMsgAttachmentBackfill::STATUS_FAILED,
+                        'last_msg_id' => $lastId,
+                    ];
+                }
+
+                $lastId = intval($message->id);
+                $processed++;
+                $attachmentCount += $count;
+                if ($count === 0) {
+                    $emptyCount++;
+                }
+            }
+
+            $state->update([
+                'last_msg_id' => $lastId,
+                'processed_count' => $processed,
+                'attachment_count' => $attachmentCount,
+                'empty_count' => $emptyCount,
+                'retry_count' => 0,
+                'last_error' => null,
+            ]);
+        }
+
+        if ($lastId >= $before) {
+            return self::complete($state, $before, $processed, $attachmentCount, $emptyCount);
+        }
+
+        $state->update(['status' => WebSocketDialogMsgAttachmentBackfill::STATUS_PENDING]);
+        return [
+            'status' => WebSocketDialogMsgAttachmentBackfill::STATUS_PENDING,
+            'last_msg_id' => $lastId,
+            'processed_count' => $processed,
+            'attachment_count' => $attachmentCount,
+        ];
+    }
+
+    private static function complete(
+        WebSocketDialogMsgAttachmentBackfill $state,
+        int $before,
+        int $processed,
+        int $attachmentCount,
+        int $emptyCount
+    ): array {
+        $state->update([
+            'status' => WebSocketDialogMsgAttachmentBackfill::STATUS_COMPLETED,
+            'last_msg_id' => $before,
+            'processed_count' => $processed,
+            'attachment_count' => $attachmentCount,
+            'empty_count' => $emptyCount,
+            'retry_count' => 0,
+            'last_error' => null,
+            'next_retry_at' => null,
+            'completed_at' => now(),
+        ]);
+
+        return [
+            'status' => WebSocketDialogMsgAttachmentBackfill::STATUS_COMPLETED,
+            'last_msg_id' => $before,
+            'processed_count' => $processed,
+            'attachment_count' => $attachmentCount,
+        ];
+    }
+
+    private static function fail(
+        WebSocketDialogMsgAttachmentBackfill $state,
+        int $lastId,
+        int $processed,
+        int $attachmentCount,
+        int $emptyCount,
+        \Throwable $error
+    ): void {
+        $retryCount = intval($state->retry_count) + 1;
+        $retryMinutes = min(30, 2 ** min(4, $retryCount - 1));
+        $state->update([
+            'status' => WebSocketDialogMsgAttachmentBackfill::STATUS_FAILED,
+            'last_msg_id' => $lastId,
+            'processed_count' => $processed,
+            'attachment_count' => $attachmentCount,
+            'empty_count' => $emptyCount,
+            'failure_count' => intval($state->failure_count) + 1,
+            'retry_count' => $retryCount,
+            'last_error' => mb_substr($error->getMessage(), 0, 2000),
+            'next_retry_at' => now()->addMinutes($retryMinutes),
+        ]);
+    }
+}
diff --git a/app/Services/MessageAttachmentService.php b/app/Services/MessageAttachmentService.php
new file mode 100644
index 000000000..67e678ac2
--- /dev/null
+++ b/app/Services/MessageAttachmentService.php
@@ -0,0 +1,236 @@
+<?php
+
+namespace App\Services;
+
+use App\Models\File;
+use App\Models\WebSocketDialogMsg;
+use App\Models\WebSocketDialogMsgAttachment;
+use App\Module\Base;
+use DOMDocument;
+use DOMElement;
+use DOMXPath;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Log;
+
+class MessageAttachmentService
+{
+    /**
+     * 从消息内容提取可检索附件。返回值不包含消息关联字段和时间字段。
+     */
+    public static function extract(string $messageType, array $messageData): array
+    {
+        if ($messageType === 'file') {
+            $attachment = self::extractFileMessage($messageData);
+            return $attachment ? [$attachment] : [];
+        }
+
+        if ($messageType !== 'text') {
+            return [];
+        }
+
+        return self::extractInlineImages((string)($messageData['text'] ?? ''));
+    }
+
+    /**
+     * 将一条消息的附件索引同步为当前内容，重复执行不会产生重复记录。
+     */
+    public static function sync(WebSocketDialogMsg $message, bool $removeMissing = true): int
+    {
+        $messageData = Base::json2array($message->getRawOriginal('msg'));
+        $attachments = self::extract((string)$message->type, $messageData);
+        if (empty($attachments) && !$removeMissing) {
+            return 0;
+        }
+
+        DB::transaction(function () use ($message, $attachments) {
+            if (empty($attachments)) {
+                WebSocketDialogMsgAttachment::whereMsgId($message->id)->delete();
+                return;
+            }
+
+            $now = now();
+            $sourceType = $attachments[0]['source_type'];
+            $positions = [];
+            $rows = [];
+            foreach ($attachments as $attachment) {
+                $positions[] = $attachment['position'];
+                $rows[] = array_merge($attachment, [
+                    'msg_id' => intval($message->id),
+                    'dialog_id' => intval($message->dialog_id),
+                    'created_at' => $message->created_at ?: $now,
+                    'updated_at' => $now,
+                ]);
+            }
+
+            DB::table('web_socket_dialog_msg_attachments')->upsert(
+                $rows,
+                ['msg_id', 'source_type', 'position'],
+                ['dialog_id', 'kind', 'name', 'ext', 'path', 'thumb', 'size', 'width', 'height', 'updated_at']
+            );
+
+            WebSocketDialogMsgAttachment::whereMsgId($message->id)
+                ->where(function ($query) use ($sourceType, $positions) {
+                    $query->where('source_type', '!=', $sourceType)
+                        ->orWhereNotIn('position', $positions);
+                })
+                ->delete();
+        });
+
+        return count($attachments);
+    }
+
+    /**
+     * 双写失败不影响聊天主链路，历史回填命令可再次同步失败消息。
+     */
+    public static function syncSafely(WebSocketDialogMsg $message, bool $removeMissing = false): bool
+    {
+        if (!in_array($message->type, ['file', 'text'], true)) {
+            return true;
+        }
+
+        try {
+            self::sync($message, $removeMissing);
+            return true;
+        } catch (\Throwable $e) {
+            Log::warning('Message attachment sync failed', [
+                'msg_id' => intval($message->id),
+                'dialog_id' => intval($message->dialog_id),
+                'message' => $e->getMessage(),
+            ]);
+            return false;
+        }
+    }
+
+    private static function extractFileMessage(array $messageData): ?array
+    {
+        $path = self::normalizeStoredPath((string)($messageData['path'] ?? ''));
+        if ($path === '') {
+            return null;
+        }
+
+        $ext = strtolower((string)($messageData['ext'] ?? self::pathExtension($path)));
+        $thumb = self::normalizeStoredPath((string)($messageData['thumb'] ?? ''));
+
+        return [
+            'source_type' => WebSocketDialogMsgAttachment::SOURCE_FILE_MESSAGE,
+            'kind' => in_array($ext, File::imageExt, true)
+                ? WebSocketDialogMsgAttachment::KIND_IMAGE
+                : WebSocketDialogMsgAttachment::KIND_FILE,
+            'position' => 0,
+            'name' => (string)($messageData['name'] ?? ''),
+            'ext' => $ext,
+            'path' => $path,
+            'thumb' => $thumb,
+            'size' => max(0, intval($messageData['size'] ?? 0)),
+            'width' => max(0, intval($messageData['width'] ?? 0)),
+            'height' => max(0, intval($messageData['height'] ?? 0)),
+        ];
+    }
+
+    private static function extractInlineImages(string $html): array
+    {
+        if ($html === '') {
+            return [];
+        }
+
+        $attachments = [];
+        if (str_contains($html, '<img')) {
+            $document = new DOMDocument('1.0', 'UTF-8');
+            $previous = libxml_use_internal_errors(true);
+            $loaded = $document->loadHTML(
+                '<?xml encoding="UTF-8"><div>' . $html . '</div>',
+                LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD | LIBXML_NOERROR | LIBXML_NOWARNING
+            );
+            libxml_clear_errors();
+            libxml_use_internal_errors($previous);
+
+            if ($loaded) {
+                $nodes = (new DOMXPath($document))->query(
+                    "//img[contains(concat(' ', normalize-space(@class), ' '), ' browse ')]"
+                );
+                foreach ($nodes ?: [] as $node) {
+                    if (!$node instanceof DOMElement) {
+                        continue;
+                    }
+                    self::appendInlineImage($attachments, [
+                        'src' => $node->getAttribute('src'),
+                        'width' => $node->getAttribute('width'),
+                        'height' => $node->getAttribute('height'),
+                        'name' => $node->getAttribute('alt'),
+                    ]);
+                }
+            }
+        }
+
+        if (empty($attachments)) {
+            preg_match_all('/\[:IMAGE:browse:([^:]*):([^:]*):(.*?):(.*?):\]/i', $html, $matches, PREG_SET_ORDER);
+            foreach ($matches as $match) {
+                self::appendInlineImage($attachments, [
+                    'src' => $match[3] ?? '',
+                    'width' => $match[1] ?? 0,
+                    'height' => $match[2] ?? 0,
+                    'name' => $match[4] ?? '',
+                ]);
+            }
+        }
+
+        foreach ($attachments as $position => &$attachment) {
+            $attachment['position'] = $position;
+        }
+        unset($attachment);
+
+        return $attachments;
+    }
+
+    private static function appendInlineImage(array &$attachments, array $image): void
+    {
+        $thumb = self::normalizeStoredPath(html_entity_decode(trim((string)$image['src']), ENT_QUOTES | ENT_HTML5));
+        if ($thumb === '' || str_contains($thumb, 'images/other/imgerr.jpg')) {
+            return;
+        }
+
+        $path = Base::thumbRestore($thumb);
+        $attachments[] = [
+            'source_type' => WebSocketDialogMsgAttachment::SOURCE_INLINE_IMAGE,
+            'kind' => WebSocketDialogMsgAttachment::KIND_IMAGE,
+            'position' => 0,
+            'name' => trim(strip_tags((string)$image['name'])),
+            'ext' => self::pathExtension($path),
+            'path' => $path,
+            'thumb' => $thumb,
+            'size' => self::localFileSize($path),
+            'width' => max(0, intval($image['width'])),
+            'height' => max(0, intval($image['height'])),
+        ];
+    }
+
+    private static function normalizeStoredPath(string $path): string
+    {
+        $path = trim(str_replace('{{RemoteURL}}', '', $path));
+        if ($path === '' || str_starts_with($path, 'data:')) {
+            return '';
+        }
+
+        $path = Base::unFillUrl($path);
+        if (str_starts_with($path, '/') && !str_starts_with($path, '//')) {
+            $path = ltrim($path, '/');
+        }
+        return $path;
+    }
+
+    private static function pathExtension(string $path): string
+    {
+        $urlPath = parse_url($path, PHP_URL_PATH);
+        return strtolower(pathinfo(urldecode((string)($urlPath ?: $path)), PATHINFO_EXTENSION));
+    }
+
+    private static function localFileSize(string $path): int
+    {
+        if ($path === '' || preg_match('/^[a-z][a-z0-9+.-]*:\/\//i', $path)) {
+            return 0;
+        }
+
+        $file = public_path(ltrim($path, '/'));
+        return is_file($file) ? max(0, intval(filesize($file))) : 0;
+    }
+}
diff --git a/app/Tasks/MessageAttachmentBackfillTask.php b/app/Tasks/MessageAttachmentBackfillTask.php
new file mode 100644
index 000000000..767a00222
--- /dev/null
+++ b/app/Tasks/MessageAttachmentBackfillTask.php
@@ -0,0 +1,22 @@
+<?php
+
+namespace App\Tasks;
+
+use App\Services\MessageAttachmentBackfillService;
+
+class MessageAttachmentBackfillTask extends AbstractTask
+{
+    public function __construct()
+    {
+        parent::__construct();
+    }
+
+    public function start()
+    {
+        MessageAttachmentBackfillService::processAutomatic();
+    }
+
+    public function end()
+    {
+    }
+}
diff --git a/database/migrations/2026_08_04_000001_create_web_socket_dialog_msg_attachments_table.php b/database/migrations/2026_08_04_000001_create_web_socket_dialog_msg_attachments_table.php
new file mode 100644
index 000000000..0171b896c
--- /dev/null
+++ b/database/migrations/2026_08_04_000001_create_web_socket_dialog_msg_attachments_table.php
@@ -0,0 +1,37 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('web_socket_dialog_msg_attachments', function (Blueprint $table) {
+            $table->bigIncrements('id');
+            $table->unsignedBigInteger('msg_id')->comment('消息ID');
+            $table->unsignedBigInteger('dialog_id')->comment('会话ID');
+            $table->string('source_type', 20)->comment('来源类型：file_message、inline_image');
+            $table->string('kind', 20)->comment('附件类型：file、image');
+            $table->unsignedSmallInteger('position')->default(0)->comment('消息内附件顺序');
+            $table->string('name')->default('')->comment('附件名称');
+            $table->string('ext', 20)->default('')->comment('文件扩展名');
+            $table->text('path')->nullable()->comment('原文件地址');
+            $table->text('thumb')->nullable()->comment('缩略图地址');
+            $table->unsignedBigInteger('size')->default(0)->comment('文件大小(B)');
+            $table->unsignedInteger('width')->default(0)->comment('图片宽度');
+            $table->unsignedInteger('height')->default(0)->comment('图片高度');
+            $table->timestamps();
+
+            $table->unique(['msg_id', 'source_type', 'position'], 'uniq_ws_msg_attachment_position');
+            $table->index(['dialog_id', 'id'], 'idx_ws_msg_attachment_dialog');
+            $table->index(['kind', 'id'], 'idx_ws_msg_attachment_kind');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('web_socket_dialog_msg_attachments');
+    }
+};
diff --git a/database/migrations/2026_08_04_000002_create_web_socket_dialog_msg_attachment_backfills_table.php b/database/migrations/2026_08_04_000002_create_web_socket_dialog_msg_attachment_backfills_table.php
new file mode 100644
index 000000000..b81567abf
--- /dev/null
+++ b/database/migrations/2026_08_04_000002_create_web_socket_dialog_msg_attachment_backfills_table.php
@@ -0,0 +1,47 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('web_socket_dialog_msg_attachment_backfills', function (Blueprint $table) {
+            $table->bigIncrements('id');
+            $table->string('status', 20)->default('pending')->comment('状态：pending、running、failed、completed');
+            $table->unsignedBigInteger('before_msg_id')->default(0)->comment('启动时消息快照上界');
+            $table->unsignedBigInteger('last_msg_id')->default(0)->comment('已处理到的消息ID');
+            $table->unsignedBigInteger('processed_count')->default(0)->comment('成功处理消息数');
+            $table->unsignedBigInteger('attachment_count')->default(0)->comment('已索引附件数');
+            $table->unsignedBigInteger('empty_count')->default(0)->comment('无有效附件消息数');
+            $table->unsignedBigInteger('failure_count')->default(0)->comment('失败尝试次数');
+            $table->unsignedInteger('retry_count')->default(0)->comment('当前消息连续重试次数');
+            $table->text('last_error')->nullable()->comment('最近一次错误');
+            $table->timestamp('started_at')->nullable()->comment('首次开始时间');
+            $table->timestamp('completed_at')->nullable()->comment('完成时间');
+            $table->timestamp('next_retry_at')->nullable()->comment('下次重试时间');
+            $table->timestamps();
+
+            $table->index(['status', 'next_retry_at'], 'idx_ws_msg_attachment_backfill_pending');
+        });
+
+        $beforeMsgId = intval(DB::table('web_socket_dialog_msgs')->max('id'));
+        $now = now();
+        DB::table('web_socket_dialog_msg_attachment_backfills')->insert([
+            'status' => $beforeMsgId > 0 ? 'pending' : 'completed',
+            'before_msg_id' => $beforeMsgId,
+            'last_msg_id' => 0,
+            'completed_at' => $beforeMsgId > 0 ? null : $now,
+            'created_at' => $now,
+            'updated_at' => $now,
+        ]);
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('web_socket_dialog_msg_attachment_backfills');
+    }
+};
diff --git a/tests/Feature/MessageAttachmentBackfillServiceTest.php b/tests/Feature/MessageAttachmentBackfillServiceTest.php
new file mode 100644
index 000000000..7b7fae33b
--- /dev/null
+++ b/tests/Feature/MessageAttachmentBackfillServiceTest.php
@@ -0,0 +1,87 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Models\WebSocketDialogMsg;
+use App\Models\WebSocketDialogMsgAttachment;
+use App\Models\WebSocketDialogMsgAttachmentBackfill;
+use App\Services\MessageAttachmentBackfillService;
+use Illuminate\Foundation\Testing\DatabaseTransactions;
+use Tests\TestCase;
+
+class MessageAttachmentBackfillServiceTest extends TestCase
+{
+    use DatabaseTransactions;
+
+    public function test_automatic_backfill_advances_persisted_cursor_to_completion(): void
+    {
+        $fileMessage = $this->makeMessage('file', [
+            'name' => 'backfill.pdf',
+            'ext' => 'pdf',
+            'path' => 'uploads/test/backfill.pdf',
+            'size' => 1024,
+        ]);
+        $imageMessage = $this->makeMessage('text', [
+            'text' => '<p><img class="browse" width="320" height="180" src="uploads/test/backfill.png_thumb.jpg"/></p>',
+        ]);
+
+        $state = WebSocketDialogMsgAttachmentBackfill::query()->firstOrFail();
+        $state->update([
+            'status' => WebSocketDialogMsgAttachmentBackfill::STATUS_PENDING,
+            // 模拟迁移后、服务重启前又产生了一条图片消息。
+            'before_msg_id' => $fileMessage->id,
+            'last_msg_id' => $fileMessage->id - 1,
+            'processed_count' => 0,
+            'attachment_count' => 0,
+            'empty_count' => 0,
+            'failure_count' => 0,
+            'retry_count' => 0,
+            'last_error' => null,
+            'started_at' => null,
+            'completed_at' => null,
+            'next_retry_at' => null,
+        ]);
+
+        $result = MessageAttachmentBackfillService::processAutomatic(1, 5);
+
+        $state->refresh();
+        $this->assertSame(WebSocketDialogMsgAttachmentBackfill::STATUS_COMPLETED, $result['status']);
+        $this->assertSame(WebSocketDialogMsgAttachmentBackfill::STATUS_COMPLETED, $state->status);
+        $this->assertSame($imageMessage->id, $state->before_msg_id);
+        $this->assertSame($imageMessage->id, $state->last_msg_id);
+        $this->assertSame(2, $state->processed_count);
+        $this->assertSame(2, $state->attachment_count);
+        $this->assertNotNull($state->completed_at);
+        $this->assertSame(2, WebSocketDialogMsgAttachment::whereIn('msg_id', [
+            $fileMessage->id,
+            $imageMessage->id,
+        ])->count());
+    }
+
+    public function test_automatic_backfill_waits_until_retry_time(): void
+    {
+        $state = WebSocketDialogMsgAttachmentBackfill::query()->firstOrFail();
+        $state->update([
+            'status' => WebSocketDialogMsgAttachmentBackfill::STATUS_FAILED,
+            'next_retry_at' => now()->addMinutes(5),
+        ]);
+
+        $result = MessageAttachmentBackfillService::processAutomatic(1, 1);
+
+        $this->assertSame('waiting', $result['status']);
+        $this->assertSame(WebSocketDialogMsgAttachmentBackfill::STATUS_FAILED, $state->fresh()->status);
+    }
+
+    private function makeMessage(string $type, array $data): WebSocketDialogMsg
+    {
+        $message = WebSocketDialogMsg::createInstance([
+            'dialog_id' => 0,
+            'userid' => 0,
+            'type' => $type,
+            'key' => '',
+            'msg' => json_encode($data, JSON_UNESCAPED_UNICODE),
+        ]);
+        $message->save();
+        return $message;
+    }
+}
diff --git a/tests/Unit/MessageAttachmentServiceTest.php b/tests/Unit/MessageAttachmentServiceTest.php
new file mode 100644
index 000000000..f246fad57
--- /dev/null
+++ b/tests/Unit/MessageAttachmentServiceTest.php
@@ -0,0 +1,85 @@
+<?php
+
+namespace Tests\Unit;
+
+use App\Models\WebSocketDialogMsgAttachment;
+use App\Services\MessageAttachmentService;
+use Tests\TestCase;
+
+class MessageAttachmentServiceTest extends TestCase
+{
+    public function test_extracts_file_message_metadata(): void
+    {
+        $attachments = MessageAttachmentService::extract('file', [
+            'name' => '方案.pdf',
+            'ext' => 'PDF',
+            'path' => 'uploads/chat/202608/1/plan.pdf',
+            'thumb' => 'images/ext/pdf.png',
+            'size' => 2048,
+        ]);
+
+        $this->assertCount(1, $attachments);
+        $this->assertSame(WebSocketDialogMsgAttachment::SOURCE_FILE_MESSAGE, $attachments[0]['source_type']);
+        $this->assertSame(WebSocketDialogMsgAttachment::KIND_FILE, $attachments[0]['kind']);
+        $this->assertSame('pdf', $attachments[0]['ext']);
+        $this->assertSame(2048, $attachments[0]['size']);
+    }
+
+    public function test_classifies_uploaded_image_as_image_attachment(): void
+    {
+        $attachments = MessageAttachmentService::extract('file', [
+            'name' => 'design.png',
+            'ext' => 'png',
+            'path' => 'uploads/chat/202608/1/design.png',
+            'thumb' => 'uploads/chat/202608/1/design.png_thumb.jpg',
+            'size' => 4096,
+            'width' => 1200,
+            'height' => 800,
+        ]);
+
+        $this->assertSame(WebSocketDialogMsgAttachment::KIND_IMAGE, $attachments[0]['kind']);
+        $this->assertSame(1200, $attachments[0]['width']);
+        $this->assertSame(800, $attachments[0]['height']);
+    }
+
+    public function test_extracts_each_browse_image_and_ignores_emoticons(): void
+    {
+        $html = <<<'HTML'
+<p>
+    <img class="browse" width="640" height="480" src="{{RemoteURL}}uploads/chat/202608/1/design.png_thumb.jpg" alt="设计图"/>
+    <img class="emoticon" width="32" height="32" src="images/emoji/smile.png" alt="笑脸"/>
+    <img class="browse extra" width="320" height="240" src="{{RemoteURL}}uploads/chat/202608/1/design.png_thumb.jpg" alt="重复图片"/>
+</p>
+HTML;
+
+        $attachments = MessageAttachmentService::extract('text', ['text' => $html]);
+
+        $this->assertCount(2, $attachments);
+        $this->assertSame([0, 1], array_column($attachments, 'position'));
+        $this->assertSame('uploads/chat/202608/1/design.png', $attachments[0]['path']);
+        $this->assertSame('uploads/chat/202608/1/design.png_thumb.jpg', $attachments[0]['thumb']);
+        $this->assertSame('设计图', $attachments[0]['name']);
+        $this->assertSame('重复图片', $attachments[1]['name']);
+    }
+
+    public function test_extracts_legacy_image_token(): void
+    {
+        $attachments = MessageAttachmentService::extract('text', [
+            'text' => '<p>旧消息</p>[:IMAGE:browse:120:80:uploads/chat/202001/1/legacy.webp:旧截图:]',
+        ]);
+
+        $this->assertCount(1, $attachments);
+        $this->assertSame('uploads/chat/202001/1/legacy.webp', $attachments[0]['path']);
+        $this->assertSame('webp', $attachments[0]['ext']);
+        $this->assertSame(120, $attachments[0]['width']);
+        $this->assertSame(80, $attachments[0]['height']);
+    }
+
+    public function test_ignores_broken_placeholder_and_non_attachment_messages(): void
+    {
+        $this->assertSame([], MessageAttachmentService::extract('text', [
+            'text' => '<img class="browse" width="90" height="90" src="images/other/imgerr.jpg"/>',
+        ]));
+        $this->assertSame([], MessageAttachmentService::extract('meeting', ['name' => '周会']));
+    }
+}