Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
Ralpha Image Resizer - High-speed image batch conversion tool
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
Pixlr - Pixlr® makes it easy to transform everyday images into stunning works of art.
Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.