Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
Polarr - MacOS, Windows, iOS, Android and online photo editing tools & free photo editors.
Optimus.io - Lossless image optimization
Fotor - Fotor is an all in one visual platform. It includes photo editor, collage maker, and graphic designer. You are free to make a visual look more beautiful.
OptiMole - Optimole makes your images weigh even 80% less while looking just as good!