Look around the forum and you'll see that there are no image sigs. I don't think there's a rule preventing it but if the same thing can be said in text it'll probably go over better both because images slow down load times (yeah I know there are a ton of image threads but unlike a sig not every post has one) and because many people consider visual sigs distracting at best and ugly at worst, no matter how artistic you think it is. Just food for thought.
There are no good guns. There are no bad guns. Any gun in the hands of a bad man is a bad thing. Any gun in the hands of a decent person is no threat to anybody — except bad people...
- Charlton Heston, on NBC's Meet the Press, May 18, 1997