ImageOptim - Faster web pages and apps.
FILEminimizer Pictures - FILEminimizer Pictures compresses JPEG photos, TIFF, BMP and PNG images and pictures by up to 98%.
OptiPNG - OptiPNG is a command-line PNG optimizer that recompresses image files to a smaller size, without...
Shrink O'Matic - Shrink O'Matic is an AIR application to easily (batch) resize (shrink) images.
TruePNG - Command-line PNG optimizer.
Pinga - Think it, get it. Get Anything Delivered.