Piio - Generates responsive images so you don't have to optimize
DVDVideoSoft Image Convert and Resize - Free Image Convert and Resize is a compact yet powerful program for batch mode image processing.
Imagify - Optimize and resize images online and through your CMS.
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
Crunch - Crunch is a No Judgment Gym that believes in making serious exercise fun by fusing fitness and entertainment. Join Crunch for all your fitness needs!
Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.