First off - that means you have too big of an attachment. Shrink it a bit.
Tip #1: Crop around the picture until it's showing only the portion that means anything.
Tip #2: Convert it to JPG if it's a PNG or BMP.

Secondly, I'll warn you - people tend to post requests, but no one seems to have the skill necessary (or maybe just the time necessary) to do the job. I will say, though, to try www.gamingw.net and search their facesets.. hopefully you'll find one close enough that you'll be able to edit it to suit your needs.