MediaWiki/variable logos

Hello, I have recently customize a style sheet for my wiki, and would love to be able to change out the logo dependant on some property set on the page, the category perhaps. However I have no idea how to do this, and lack the programming skills to try. If anyone knows how to do this, I would be willing to pay (via paypal) anyone that knows how to do this.

My email address is lara@sanctuaryshard.com, please include the cost in your email, and here is the wiki: http://www.sanctuaryshard.com/wiki/index.php?title=Main_Page

Hi, i have implemented a simple example of your request. check out this: Go to a page on this wiki in Category:GNU, you should see a GNU head appearing in our logo, unlike on other pages. Also try pages in Category:ASCII. Those are just random examples. Source code changes i made follow: