ImageOptim - Faster web pages and apps.
IrfanView - IrfanView ... one of the most popular viewers worldwide.
OptiPNG - OptiPNG is a command-line PNG optimizer that recompresses image files to a smaller size, without...
ImageGlass - You can use Image to view your digital images and photos of many different formats.
TruePNG - Command-line PNG optimizer.
Universal Viewer - Universal Viewer is an advanced file viewer for wide range of formats. Supported file formats are: