Jiffy Gallery Press

Setup image galleries in a jiffy via shortcodes specifying image slugs, and
have the images load in a jiffy by downloading only the minimum size image
necessary for the client viewport size. Images are rendered as large as
possible within the viewport when expanded.

No locked premium features, and tested to work on iOS devices.

Demo at: http://www.maratbn.com/projects/jiffy-gallery-press/#demo

Official project URLs:

https://wordpress.org/plugins/jiffy-gallery-press
https://github.com/maratbn/JiffyGalleryPress
http://www.maratbn.com/projects/jiffy-gallery-press