Vallen jpegger - Vallen JPegger is the international, handy, and full featured image viewer, which shouldn't be...
ImageOptim - Faster web pages and apps.
Cloudimage - Cloudimage.io is the easiest way to resize, store, and deliver your images to your customers through a rocket fast CDN.
OptiPNG - OptiPNG is a command-line PNG optimizer that recompresses image files to a smaller size, without...
TruePNG - Command-line PNG optimizer.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!