What algorithm did Windows XP use to choose your initial user picture?

The times when people spent an extra brain cycle to avoid billions of second passes.

Does it also check existing users so you don't match one?

100 seems like a very unnecessarily low limit, even for the time

A couple of screenshots would've been useful for the post-millennial generations that never got to see the "beauty" (cough) of XP.

Some say the Admin account defaulted to a chessboard.

I think it's true, but not sure if I'm just falling victim to false memories... help?