Pngquant

Converts 32-bit RGBA PNGs into 8-bit RGBA-palette PNGs

pngquant is a command-line utility to quantize and dither 32-bit RGBA PNGs down to 8-bit or smaller RGBA-palette PNGs, usually with a significant reduction in file size 40-70 smaller than 24-bit PNGs.

This unique type of PNG supports full alpha transparency and is compatible with all modern web browsers, and has better fallback in IE6 than 24-bit PNGs.

Features

• High-quality palette generation using modernized Median Cut algorithm.
• Unique dithering algorithm that adds less noise to images than the standard Floyd-Steinberg.
• Easy to integrate with shell scripts, GUIs and server-side software.
• Fast mode for processing large numbers of images.

WWW http//pngquant.org/