Kaleidoscope: File comparison for Mac

This app saved my life more than once lately...

Built by Black Pixel, Kaleidoscope can be used to spot the differences in text and image files. Review changes in seconds with this advanced file comparison application. Compare text in Blocks, Fluid and Unified layouts. Quickly navigate and search through the most readable diff you’ve ever seen. With four different layouts and exceptional performance, Kaleidoscope makes reviewing image files that much easier and quicker. Each layout aids the eye in a different way, to help you quickly spot anything, from the smallest retouch to image-wide color changes.