Select a tag to browse associated projects and drill deeper into the tag cloud.
The pngquant PNG optimisation tool. It converts 24/32-bit PNG files to smaller, paletted PNG8 files with alpha transparency.
PNGoo (pronounced pin-goo) is a GUI for various command-line PNG compressors. There's a preview release available on the downloads page. Feel free to post and issues / feature requests.
ImageAlpha is a GUI for pngnq and pngquant. It allows you to easily generate paletted PNG images with full alpha channel and easily preview them against multiple backgrounds, to find optimum number of colors.