Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
Batch Image Resizer - Resize, crop, shrink, flip, exif-rotate, convert, enhance, process multiple pictures and photos with professional software! 120+ Actions, 30+ Image Formats
ACDSee - ACDSee is an image viewer that uses very little system resources, and it has a small, sleek size that won't take up much space on your system.
Phatch - Phatch = Photo & Batch!