Second name is OptiPng. it's PNG optimization tools which you can run from the command line exist. checkout http://www.phpied.com/png-optimization-tools/ & http://optipng.sourceforge.net/
Third name is CSSEmbed. It's tool to automatically embed images into CSS files as data URIs. This is a very small, simple tool that reads in a CSS file, identifies the images referenced within, converts them to data URIs, and outputs the resulting style sheet. The newly-created stylesheet is an exact duplicate of the original, complete with comments and indentation intact; the only difference is that all references to image files have been replaced with data URIs. download it from http://github.com/nzakas/cssembed/
Fourth one is used for optimization jpeg files using a tool like JPEGtran. it covers following tasks.
- tripping meta data (meta is sometimes bulky and useless for web display)
- Optimizing Huffman tables or
- Convert a JPEG to progressive encoding
read more how use JPEGtran http://www.phpied.com/installing-jpegtran-mac-unix-linux/