diff --git a/fam-edge/src/fam_edge/api_gateway/api_gateway.py b/fam-edge/src/fam_edge/api_gateway/api_gateway.py
index fdd680d..c349c03 100644
--- a/fam-edge/src/fam_edge/api_gateway/api_gateway.py
+++ b/fam-edge/src/fam_edge/api_gateway/api_gateway.py
@@ -141,11 +141,23 @@ def event_thumb(event_id):
 
     由 video_processor 处理成功后按事件时间戳定位视频帧生成：
     /opt/fam-edge/thumbs/ev_{event_id}.jpg
+    若该事件截图缺失（如旧事件/未生成），兜底返回所属视频的首帧缩略图
+    thumbs/{video_id}.jpg，避免前端图片空白。
     """
     if not _check_token():
         return jsonify({"error": "unauthorized"}), 401
     path = f"/opt/fam-edge/thumbs/ev_{event_id}.jpg"
     if not os.path.isfile(path):
+        # 兜底：查事件所属视频，返回视频首帧缩略图
+        try:
+            row = state.get_db()._conn.execute(
+                "SELECT video_id FROM events WHERE id=?", (event_id,)).fetchone()
+            if row and row['video_id']:
+                vpath = f"/opt/fam-edge/thumbs/{row['video_id']}.jpg"
+                if os.path.isfile(vpath):
+                    return send_file(vpath, mimetype='image/jpeg')
+        except Exception:
+            pass
         return jsonify({"error": "thumb_not_found"}), 404
     return send_file(path, mimetype='image/jpeg')