You can also use MC to change their outfit to whatever category you want before getting the autograph. Makes it a little more personal than everyone having the same image. Especially if you makeover townies/premades.
The frame colour is random on the framed ones, I think. Sometimes it's brown, sometimes it's white.
On lower levelled celebrities you get unframed signed pics. Mid-range one is like a CL flyer/poster (you can size it up a couple of times if you want it bigger). Low level one is a signed photo that just lies on a surface rather than on the wall.