Converseen is a cross-platform image processing software that converts image file formats. Converseen does this by resizing, renaming and reshaping images. All it takes is a click at your mouse.

Image Tuner is a free batch image resizing, renaming, conversion and watermarking software with a super-intuitive and straightforward interface.

Shrink O'Matic. Shrink O'Matic is an AIR application to easily (batch) resize (shrink) images. It handles JPGs, GIFs and PNGs. Simply drag and drop images and they'll be resized as you wish! Options

Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!