Shrink O'Matic - Shrink O'Matic is an AIR application to easily (batch) resize (shrink) images.
Optimage - Advanced image optimization tool
Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.
ImageOptim API - Web service for image compression
ImageOptim - Faster web pages and apps.
Imagify - Optimize and resize images online and through your CMS.