Yeah, they could work, as long as they arn't ridiculously big. But i reckon it would be better without images.. makes the site look neater imo.
The only real reason I disabled them was the fact that I thought it was so ridiculously dire for people to disable sigs and yet still have their own. I could probably code it in so that didn't happen... can't really be bothered however.
I would be for not having sigs. They make the forum look messy a lot of the time and make you have to scroll through more than just posts.
Well, Im on a soccer forum, and they have guidelines of 300X100 for Sigs, or 5 lines of text, and if they are broken the person lose's the right to Avatar's and Signatures for a month. Makes it look really neat.