DVDVideoSoft Image Convert and Resize - Free Image Convert and Resize is a compact yet powerful program for batch mode image processing.
ImageOptim - Faster web pages and apps.
Ralpha Image Resizer - High-speed image batch conversion tool
OptiPNG - OptiPNG is a command-line PNG optimizer that recompresses image files to a smaller size, without...
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
TruePNG - Command-line PNG optimizer.