I wanted a reasonably sized photographic image with a 24-bit alpha channel. So I used a JPEG for what JPEGs are good for and a PNG for what PNGs are good for…

ImageOptim optimizes images — so they take up less disk space and load faster — by finding best compression parameters and by removing unnecessary comments and color profiles. It handles PNG, JPEG and GIF animations.

Join the animated PNG movement.

Well, now you can add decent PNG support to IE5.5+ on Windows with no changes to your website HTML source code. This script will add near-native PNG support with full alpha opacity, with only one line in your CSS file, that applies to all <img> tags and a