diff --git a/dlibrary/static/viewer.js b/dlibrary/static/viewer.js
index 721a148..a4986ac 100644
--- a/dlibrary/static/viewer.js
+++ b/dlibrary/static/viewer.js
@@ -88,8 +88,9 @@ document.addEventListener('DOMContentLoaded', () => {
         elapsed = 0;
         updateBar();
 
-        if (pageNum >= IMAGES.length) {
+        if (pageNum >= IMAGES.length - 1) {
             pageNum = IMAGES.length - 1;
+            changeDuration(duration, true);
         }
         if (pageNum < 0) {
             pageNum = 0;