Update README.md

Author: arnowelzel

README.md

@@ -4,7 +4,7 @@ This plugin adds a fullscreen display button to the UI to [PhotoSwipe 5](https:/
 
 The code is inspired by ideas described in https://github.com/dimsemenov/PhotoSwipe/issues/1759.
 
-This plugin is also used in [Lightbox with PhotoSwipe](https://wordpress.org/plugins/lightbox-photoswipe/).
+This plugin is also used in [Lightbox with PhotoSwipe](https://wordpress.org/plugins/lightbox-photoswipe/), see https://wordpress-demo.arnowelzel.de/lightbox-with-photoswipe-5/ as an example.
 
 ## Using the plugin