The second pic works better because you can see Moses in it. It's a bit small, though; you can't really make out the details of the mosaic. Could you possibly get a shot of Moses' face immediately after seeing this image? Pairing that with the second pic might would make for a better representation than either pic would alone.
I reject your requirement for a witty statement or fanboyish squealing in my signature.I don't see any way it could work with a single small image, true enough, but a series of pictures could convey this trope. Genocide Backfire is a process with easily identifiable steps: the "genocide" step and the "backfire" step. If we could get a pic of an Evil Overlord burning a village, followed by a pic of The Hero striking down the Evil Overlord, we'd be golden.
I reject your requirement for a witty statement or fanboyish squealing in my signature.

I was thinking some shots from The Prince Of Egypt, when Moses realizes that the Pharaoh killed hundreds of innocent children.
[1]
◊ [2]
◊