You can change the appearance of your SN (it defaults to all lowercase). Go to Profile -> Modify Profile -> and change to how you want it to appear.
The following is compliments of posters in various boards above:
To pic an image in your sig, type in [*URL]link to image[*/IMG] then remove the *s
To put in a link, type in [*URL=link here]Hyperlinked text[*/URL] and remove the *s
Supposedly you can just put the direct link from photobucket for the avatars but I have not tried that.
Avatars can only be 100 x 100 pixels (edit it under where you changed the URL.)
Thanks Rachel
I've been playing around with the settings, and there's a slight typo above, on putting images in siggy. The first part should actually be IMG, not URL.
To pic an image in your sig, type in [*IMG]link to image[*/IMG] then remove the *s
Also, I noticed the amount of space you have for a siggy is signifcantly less than the bump (400 characters) so I had to combine badges into one image to get them all to display. I'll play around with combining different badges over the next few days in case anyone is interested in adding them to their signature.