prevent too many image loading at save time

lib/foundation/image_provider/cached_image.dart

@@ -21,8 +21,17 @@ class CachedImageProvider
 
   final String? cid;
 
+  static int loadingCount = 0;
+
+  static const _kMaxLoadingCount = 8;
+
   @override
   Future<Uint8List> load(StreamController<ImageChunkEvent> chunkEvents) async {
+    while(loadingCount > _kMaxLoadingCount) {
+      await Future.delayed(const Duration(milliseconds: 100));
+    }
+    loadingCount++;
+    try {
       if(url.startsWith("file://")) {
         var file = File(url.substring(7));
         return file.readAsBytes();
@@ -38,6 +47,10 @@ class CachedImageProvider
       }
       throw "Error: Empty response body.";
     }
+    finally {
+      loadingCount--;
+    }
+  }
 
   @override
   Future<CachedImageProvider> obtainKey(ImageConfiguration configuration) {