Graphic sigs, if limited to under 6K in size, shouldn't cause much loading problems. However, I do understand Wvyern's point...since this tends to be a lot more of a "help" forum, we need to keep the load times low here.
For example, the graphic signature I use at General Discussions,
is 5K in size...less than a typical banner ad. Notice that I do not use this here at Wizards & Warriors, though, although I do over in General Discussions and some of the other boards where it is tolerated.
I realize that I am guilty of using graphics as well yesterday with the "fireworks"...that was a one shot deal only.
If you do find cool screenshots while running Wizards & Warriors, send them to me and I can get them up (host them even!) for a Gael Serran Examiner. It's our one graphic publication here at W&W.
Thanks, everyone!
-Sazerac