Ok, figured everything out. RickRude, your other avatar options are now available.
As far as avatar uploads go, they're turned off, and I remember now, that when the board was set up, I was a bit worried about bandwidth since I'd never hosted the board before and didn't know what kind of an impact this site would have on my hosting plan.
It turns out bandwidth really isn't an issue, but in the interests of keeping the board performing well and people not uploading gigantic files, I'm going to keep the upload off for now. Everyone should be able to link to an external source for their images. Let me know if you have any further problems.