I'd love to use a bigger signature image, but I follow the rules as stated in the Edit Signature dialogue (<= 500x100, 19.5kB).
Yet I've just seen a signature which is 790x527, 220kB.
It's at http: //pornpicer.com/files/5pl2cl6va160ooqt085i.jpg
I want one like that too.
Either the rule has been changed without changing the rule text, or the server software is not very clever. Which is it?