FILEminimizer Pictures - FILEminimizer Pictures compresses JPEG photos, TIFF, BMP and PNG images and pictures by up to 98%.
DVDVideoSoft Image Convert and Resize - Free Image Convert and Resize is a compact yet powerful program for batch mode image processing.
TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
Ralpha Image Resizer - High-speed image batch conversion tool
Compressor.io - Optimize and compress your images online. Compressor is a lossy and lossless photo compression tool.
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.