First, upload the signature to PhotoBucket or a similar site. On PhotoBucket, highlight the text like I did...



Then copy and paste it into Edit Signature in your User CP! Hope this helps!

When you paste it, it should look like this (without the *)

[IMG*]http://i3.photobucket.com/albums/y61/Crazy-Cat-Lover/ed82bfd9.gif[/IMG*]