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

There's a very handy batch script that recursively optimizes images beneath a folder using OptiPNG (from this blog):

FOR /F "tokens=*" %G IN ('dir /s /b *.png') DO optipng -nc -nb -o7 -full %G

ONE LINE!