diff --git a/adventskalender/2025/index.html b/adventskalender/2025/index.html
index 8df21d1..3123fcc 100644
--- a/adventskalender/2025/index.html
+++ b/adventskalender/2025/index.html
@@ -69,16 +69,16 @@
 
   <!-- JPEG-Fallback -->
   <img
-    src="assets/images/1366/jpeg/Basisbild.jpg"
+    src="assets/images/1366/jpeg/Basisbild.jpeg"
     srcset="
-      assets/images/480/jpeg/Basisbild.jpg 480w,
-      assets/images/720/jpeg/Basisbild.jpg 720w,
-      assets/images/1024/jpeg/Basisbild.jpg 1024w,
-      assets/images/1366/jpeg/Basisbild.jpg 1366w,
-      assets/images/1600/jpeg/Basisbild.jpg 1600w,
-      assets/images/1920/jpeg/Basisbild.jpg 1920w,
-      assets/images/2560/jpeg/Basisbild.jpg 2560w,
-      assets/images/3840/jpeg/Basisbild.jpg 3840w"
+      assets/images/480/jpeg/Basisbild.jpeg 480w,
+      assets/images/720/jpeg/Basisbild.jpeg 720w,
+      assets/images/1024/jpeg/Basisbild.jpeg 1024w,
+      assets/images/1366/jpeg/Basisbild.jpeg 1366w,
+      assets/images/1600/jpeg/Basisbild.jpeg 1600w,
+      assets/images/1920/jpeg/Basisbild.jpeg 1920w,
+      assets/images/2560/jpeg/Basisbild.jpeg 2560w,
+      assets/images/3840/jpeg/Basisbild.jpeg 3840w"
     sizes="
       (min-width: 3840px) 3840px,
       (min-width: 2560px) 2560px,