diff --git a/src/util.ts b/src/util.ts
index 9f44fef..e0b77ae 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -1,5 +1,9 @@
 export function isImageValid(src: string) {
   return new Promise(resolve => {
+    if (!src) {
+      resolve(false);
+      return;
+    }
     const img = document.createElement('img');
     img.onerror = () => resolve(false);
     img.onload = () => resolve(true);