http://www.punypng.com
PunyPNG is a free website optimization tool that dramatically reduces the file size of your images
http://farhadi.ir/works/smartoptimizer
SmartOptimizer (previously named JSmart) is a PHP library that enhances your website performance by optimizing the front end using techniques such as minifying, compression, caching, concatenation and embedding. All the work is done on the fly on demand.