ImageOptim - Faster web pages and apps.
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
jStrip - jStrip is a free tool to reduce the file size of JPEG images without sacrificing image quality.
Polarr - MacOS, Windows, iOS, Android and online photo editing tools & free photo editors.
ImageAlpha - ImageAlpha is a GUI for pngnq and pngquant.
SpotiPlus - SpotiPlus is a feature-rich application that lets you create cover arts for Spotify playlists and increase your fan following.