I've just been thinking about this... how does the original game PS save its pictures? Does it temp-save them into RAM? It seems like this isn't the case though, considering that it doesn't work.
Has anyone ever tried leaving the memory UNprotected while playing this game? It'd probably crash at some point, but I wonder if that would fix the problem.
If nothing else, I wonder if any emu authors would be willing to include some kind of hack or work-around, like special-casing the 'take snapshot' button while the game's running, to save a render-to-texture to a file in your emu directory.. and then when the game requests the images, load them from those files? It probably isn't feasible, but hey, if it could be done, it would work rather well :satisfied
I guess the only problem with that method would be, would the game be able to 'judge' the pictures in an unknown format? Hmm... weird. I guess the first step in fixing Snap would be to know just what the game is doing with the pictures...