I'll tell yaz how to do it, but you need ImageReady. Chances are if you have Photoshop you have Imageready too:
Get your photo and obviously rescale it to 50x50...
Wait...sorry I've actually forgotten already, basically you just keep making a new frame after frame (there should be an option somewhere to turn on the frame slider - or whatever it's called)
Each new frame should have the Hue value (Ctrl+U) increased by like 10-20 degrees until you come back to the same colour you started with (this gives you a nice seamless colour loop).
It has to be beneath 15k for DA to accept it but if you Optimise the animation (which imageready can do quite well) you can decrease the colours a bit and save a lot of space.
Good luck, it pays off in the end if you can pull it off don't worry you'll fly though it mate!
One more thing, increase the saturation on them all a little bit to make it more intense but don't go crazy it'l just look cheap

--
_{Hearing I ask from the holy races
From Heimdall's sons, both high and low
Thou wilt, Valfather, that well I relate
Old tales I remember of men long ago.}