diff --git a/js/haus-schleusingen.js b/js/haus-schleusingen.js
index 76b690e..1d6bf06 100644
--- a/js/haus-schleusingen.js
+++ b/js/haus-schleusingen.js
@@ -46,10 +46,11 @@ $(function () {
   // Lightbox – gallery grid items
   $(document).on("click", ".grid-item", function () {
     var src = $(this).data("img") || $(this).find("img").attr("src");
-    $("#lightboxImg").on("error", function () {
+    $("#lightboxImg").off("error").on("error", function () {
       // WebP fallback: try original format
-      var fallback = src.replace(/\.webp$/, src.endsWith('.webp') ? '.png' : '.jpg');
-      if ($(this).attr('src') !== fallback) $(this).attr('src', fallback);
+      if ($(this).attr('src').endsWith('.webp')) {
+        $(this).attr('src', src.replace(/\.webp$/, '.png'));
+      }
     });
     $("#lightboxImg").attr("src", src);
     $("#lightbox").addClass("open");
@@ -59,9 +60,10 @@ $(function () {
   // Lightbox – floor plan images in Raumaufteilung
   $(document).on("click", ".floor-plan img[data-img]", function () {
     var src = $(this).data("img");
-    $("#lightboxImg").on("error", function () {
-      var fallback = src.replace(/\.webp$/, '.png');
-      if ($(this).attr('src') !== fallback) $(this).attr('src', fallback);
+    $("#lightboxImg").off("error").on("error", function () {
+      if ($(this).attr('src').endsWith('.webp')) {
+        $(this).attr('src', src.replace(/\.webp$/, '.png'));
+      }
     });
     $("#lightboxImg").attr("src", src);
     $("#lightbox").addClass("open");