PNGGauntlet is a free PNG compression app for Windows. Create the smallest PNGs, without sacrificing any image quality.
With a very nice drag ‘n’ drop enabled user interface, the application canoptimize any given number of files pretty quickly.
It combines the algorithms of PNGOUT, OptiPNG, and DeflOpt for creating the smallest file and generates a lossless output.
The image to be minified doesn’t need to be in PNG format, other popular formats like JPG, GIF, TIFF, and BMP can be used as well for converting them to PNG.
There are also several settings for anyone looking to fine tune the compression process.
Requirements: .NET Framework 4.0+
Compatibility: Windows OS