diff --git a/app/routers/wechat_notify_api.py b/app/routers/wechat_notify_api.py
index befbc72..3813308 100644
--- a/app/routers/wechat_notify_api.py
+++ b/app/routers/wechat_notify_api.py
@@ -128,6 +128,11 @@ async def send_card(request: Request):
                 if alarm_snapshot_key:
                     presigned_url = _get_presigned_url(alarm_snapshot_key)
 
+            logger.info(f"群聊截图诊断: alarm={req.alarmId}, "
+                        f"iot_snapshot={req.snapshotUrl!r}, "
+                        f"db_snapshot={alarm_snapshot_key!r}, "
+                        f"presigned_url={presigned_url[:80] if presigned_url else '(空)'}...")
+
             # alarm_type: 用 alarm_type_code 避免"告警告警"
             actual_alarm_type = alarm_type_code or req.title
 
diff --git a/app/services/notify_dispatch.py b/app/services/notify_dispatch.py
index 78a3706..eeed834 100644
--- a/app/services/notify_dispatch.py
+++ b/app/services/notify_dispatch.py
@@ -144,10 +144,19 @@ async def process_alarm_notification(alarm_data: Dict):
 
 
 def _get_presigned_url(snapshot_url: str) -> str:
-    """将 COS object key 转为预签名 URL"""
+    """将 COS object key 或永久 URL 转为预签名 URL"""
     if not snapshot_url:
         return ""
+    # 如果是完整 COS 永久 URL，提取 object key 后重新生成预签名 URL
     if snapshot_url.startswith("http"):
+        object_key = _extract_cos_object_key(snapshot_url)
+        if object_key:
+            try:
+                from app.services.oss_storage import get_oss_storage
+                return get_oss_storage().get_presigned_url(object_key)
+            except Exception as e:
+                logger.warning(f"从COS URL生成预签名失败: {e}")
+        # 无法提取 key，返回原 URL（可能是外部 URL）
         return snapshot_url
     try:
         from app.services.oss_storage import get_oss_storage
@@ -157,6 +166,37 @@ def _get_presigned_url(snapshot_url: str) -> str:
         return snapshot_url
 
 
+def _extract_cos_object_key(url: str) -> str:
+    """从 COS 永久 URL 中提取 object key
+
+    支持格式:
+    - https://{bucket}.cos.{region}.myqcloud.com/{key}
+    - https://cos.{region}.myqcloud.com/{bucket}/{key}
+    """
+    try:
+        from urllib.parse import urlparse
+        parsed = urlparse(url)
+        host = parsed.hostname or ""
+        path = parsed.path.lstrip("/")
+
+        if not path or "myqcloud.com" not in host:
+            return ""
+
+        # 格式1: {bucket}.cos.{region}.myqcloud.com/{key}
+        if ".cos." in host and host.endswith(".myqcloud.com"):
+            return path
+
+        # 格式2: cos.{region}.myqcloud.com/{bucket}/{key}
+        if host.startswith("cos.") and host.endswith(".myqcloud.com"):
+            parts = path.split("/", 1)
+            if len(parts) == 2:
+                return parts[1]
+
+        return ""
+    except Exception:
+        return ""
+
+
 def _save_vlm_result(alarm_id: str, vlm_result: Dict):
     """将 VLM 复核结果写入 alarm_llm_analysis 表"""
     db = get_session()
diff --git a/app/services/wechat_service.py b/app/services/wechat_service.py
index 103625c..5d512d4 100644
--- a/app/services/wechat_service.py
+++ b/app/services/wechat_service.py
@@ -218,9 +218,12 @@ class WeChatService:
 
     async def upload_media_from_url(self, image_url: str) -> Optional[str]:
         """从 URL 下载图片后上传到企微，返回 media_id"""
+        logger.info(f"企微截图上传: 开始下载 url={image_url[:100]}...")
         image_data = await self._download_image(image_url)
         if not image_data:
+            logger.warning(f"企微截图上传: 下载失败，无法上传 url={image_url[:100]}")
             return None
+        logger.info(f"企微截图上传: 下载成功，size={len(image_data)} bytes，开始上传到企微")
         return await self.upload_media(image_data)
 
     # ==================== 个人消息：按钮交互型模板卡片 ====================