Basically I don´t mind, but it´s more practical to credit in the userpic section in my opinion. It´s faster to change your userpic comments than your user info and the most important thing: when I find s.o. using a GORGEOUS icon, the first thing I do is stalking his/her userpic section and see who made that icon, so that I can grab it, too, and know who to credit or where to go and find more of those gorgeous icons XD If s.o. credits in his/her user info, I might not know that I HAVE TO GO to the user profile to know where the icons come from, cuz usually the credits are with the user pics XDDD
Err~ hope you got what I wanted to say XDDDD .. but that´s just me! Don´t mind XD