diff --git a/collection/opendb-banner/collection.json b/collection/opendb-banner/collection.json
index f5b7ee5..8d7eb4d 100644
--- a/collection/opendb-banner/collection.json
+++ b/collection/opendb-banner/collection.json
@@ -9,7 +9,8 @@
         "description": "ID，系统自动生成"
       },
       "image_url": {
-        "bsonType": "string",
+        "bsonType": "file",
+        "fileMediaType": "image",
         "description": "图片url。可以是在线地址，也支持本地地址",
         "label": "图片url",
 		"trim":"both"