Hi! I'm not sure if you've fixed your signature yet or not, but this has happened to me with photobucket too.

I actually deleted the uncooperative picture and re-uploaded the same one again from our hard-drive to try to resize a "fresh" image. This seemed to work for me. I also noticed that some of my pictures on photobucket say they are different sizes but I've got no idea why this would be true. Anyway, the pictures with (1024x768) in the size line seem to resize at 50% the best for signature pictures on HB. I hope what I'm saying makes sense!

Good luck! I'll try to help if I can!

Katie