diff --git a/bricks/input.js b/bricks/input.js
index 0bedc5b..6f62261 100644
--- a/bricks/input.js
+++ b/bricks/input.js
@@ -594,7 +594,7 @@ bricks.UiImage =class extends bricks.UiFile {
 	}
 	show_image(event){
 		var params = event.params;
-		if (! params instanceof Array){
+		if (params instanceof File){
 			params = [ params ];
 		}
 		this.preview.clear_widgets();