That's him above, at around the time of JD's murder. He has a bit of a beard, but not a particularly noticeable one. He was relatively slim then, too, and capable of being smartly dressed (I seem to recall he bought a designer jacket/coat for his wedding).
I haven't seen the Crimewatch reconstruction for a while (must do that). I'm convinced it was George. He was likely in the area at the time, had form for stalking and photographing women from behind, had form for violence towards women.
He was a very dangerous man. I've never been convinced by the "low IQ" argument. I think it's perfectly possible that he was cruising the area, came upon Jill, walked up behind her with his gun and shot. It may have been an accident, even.