check image mime type

src/user.ml

@@ -255,11 +255,10 @@ let get_avatar user_id =
 let upload_avatar files user_id =
   match files with
   | [] -> Error "No file provided"
-  | [ (_, content) ] ->
-    if not (is_valid_image content) then Error "Invalid image"
-    else
-      let^ () = Db.exec Q.upload_avatar (content, user_id) in
-      Ok ()
+  | [ (name_opt, content) ] ->
+    let* _name, _alt, content = clean_image (name_opt, "avatar", content) in
+    let^ () = Db.exec Q.upload_avatar (content, user_id) in
+    Ok ()
   | _files -> Error "More than one file provided"
 
 let is_admin user_id =