How does Google's Page Speed lossless image compression work?

Question

When you run Google\'s PageSpeed plugin for Firebug/Firefox on a website it will suggest cases where an image can be losslessly compressed, and provide a link to download th

Answer 1

In my opinion the best option out there that effectively handles most image formats in a go is trimage. It effectively utilizes optipng, pngcrush, advpng and jpegoptim based on the image format and delivers near perfect lossless compression.

The implementation is pretty easy if using a command line.

sudo apt-get install trimage    
trimage -d images/*

and voila! :-)
Additionally you will find a pretty simple interface to do it manually as well.