Yahoo’s excellent Exceptional Performance series recommends optimizing images in several lossless ways:
* stripping meta data from JPEGs
* optimizing JPEG compression
* converting certain GIFs to indexed PNGs
* stripping the un-used colours from indexed images
Smush.it offers an API that performs these optimizations (except for stripping JPEG meta data) automatically, and this plugin seamlessly integrates Smush.it with WordPress.
via WordPress › WP Smush.it « WordPress Plugins.
