Compatible with 7.1.x
From the makers of Photo Organizer 7 comes Segue, a novel tweak that adds customizable slideshow animations to the Photos app. Choose from 11 of Apple's documented and undocumented transition effects, such as "cameraIris" and "pageCurl". Cycle through multiple effects, or have Segue choose random effects per transition.
Best of all, it's completely free and open-source! Developers wishing to extend the functionality of Segue can find the full source code on Bitbucket.