yeah of course! hathater taught me how to do it!
at least i think it was hathater... bas? pokemon? guldo? somebody
go to User CP
go to Edit Signature
then type [PIMG]550[PIMG] with a "/" before the "[" and the "P" of the second [PIMG]
and that'll give you the blitzle sprite
you'll have to dig around to find whatever you want
as I don't think the number correlates with the dex number (it's a little bit off i think)