It is asking a lot and the answer I give isn't that good...
I've been playing with (no it's not a profit site - I'm just checking it out for someone in another forum because I happened to see it while it was in beta and free) this:
(code tag used to not be a link which is odd, we get too much traffic at that site actually)
That is free and you DO have to grab your own games. That's the downside. So it's not really an answer to your question in a very accurate manner - sorry about that. My initial views are that it's really simple and effective. Grab the game, upload it, make a screen shot, and upload it.
The script says, VERY exact, that I can distribute it. I think I might have seen it here first.
Like I said, it's not really the answer you wanted perhaps? It is, I hope, an alternative solution and probably not a very difficult one. With game scripts, more than any other script besides maybe a few forum scripts and add-ons, watch VERY carefully for piracy...