Pixlr - Pixlr® makes it easy to transform everyday images into stunning works of art.
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
Adobe Photoshop Express - Easily edit and share your photos in no time!
IrfanView - IrfanView ... one of the most popular viewers worldwide.
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.