PhotoDemon - Lightweight portable BSD licensed photo editor for Windows focused on performance and usability.
Sketch - Professional digital design for Mac.
PhotoFlare - Quick, simple but powerful Cross Platform image editor.
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
PixBuilder - Free Photo Editing Software for PC
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.