diff --git a/web-to-ppt/capture.js b/web-to-ppt/capture.js
index 996ddbb..860a448 100644
--- a/web-to-ppt/capture.js
+++ b/web-to-ppt/capture.js
@@ -944,7 +944,7 @@
     const children = [];
     const imageCandidates = getElementImageCandidates(element);
     const currentSrc = imageCandidates[0] || null;
-    const backgroundUrls = extractStyleImageUrls(styles);
+    let backgroundUrls = extractStyleImageUrls(styles);
 
     if (/^(IMG|VIDEO|SOURCE|PICTURE)$/i.test(element.tagName)) {
       for (const url of imageCandidates) {