Pyxy-gallery is an open source PHP script to make an AJAX-based image gallery. Pyxy is using Prototype and Lightbox to create AJAX paging for images, and currently allowing to bookmark pages but not single images; but this will be probably supported in the next versions. The gallery is a single PHP script, and the install is very easy, you can see the documentation for more details. Sample gallery is available for demo, or download Pyxy-gallery to give it a try. Released under LGPL license.