To fit with my user name, I chose this pic of a pig statue. I can't quite remember where the statue came from, but it's origins is the original picture was found via Yahoo's search page from my old computer.
I used 8bitpix.com to create mine. Nothing special, and I've just always like the various Trollface meme variations; just happened to settle on the one I'm currently using. I used the same pic for several other accounts, too.