Optimize image files

Found a simple yet useful tool to optimize various image formats for web [ImageOptim](http://imageoptim.com) and out of curiosity I dragged the whole Wonder folder onto it. The result:

_Saved 2.3MB out of 9.3MB. 24.7% overall (up to 98.5% per file)_

This patch contains all optimized image files. I checked some of them and could not detect a visible difference though who knows that for all 985 files, right? ;)