Jekyll High-res Link
Jekyll High-res Link is a pluging for Jekyll that wraps images with a link that redirects them to the original uncompressed image. You require to have both versions of the image for this to work. Although you can use this script to make the two versions of the images. In v0.2.0, an implementation of this script on Ruby will be added for those that prefer a more seamless solution. More information on how to use the gem is provided at the README of the project.
I made it just to implement it on this website since I didn’t want to have any more JavaScript. If you want to hear the story behind this plugin, see my blog post about minifying this website.