PhotoSwipe is a JavaScript library that displays images in a very appealing way, including swipe navigation gestures on mobile devices such as tablets and smartphones. I felt free to create the FlatPress plugin "PhotoSwipe for FlatPress" which utilizes PhotoSwipe for displaying single images as well as image galleries. It therefore introduces the BBCode elements "photoswipeimage" and "photoswipegallery".
See the plugin working on my FlatPress site fahrrad.arvidzimmermann.de. (Note the floating single images in the text and the gallery at the bottom. And don't forget to try the cool swipe navigation with your mobile gizmo!)
To get the plugin and its documentation, visit my software site arvidzimmermann.de. I tested the plugin just for myself and would therefore appreciate comments and bug reports.