Maighstir: the thing about that, though, is that you need a fairly large library of images
and relevant metadata for the system to be effective, something I doubt GOG have, or have the resources to create.
vv221: Well, and what about
this?
Looks like a big library of images with associated metadata to me ;P
A fairly small library of images though, say there are on average 16 images per game and 2500 games, that's 40000 images, I would assume you'd want a couple orders of magnitude more than that, as well as create enough new images and switch out old ones every so often in order to make storing correct answers less effective.
Sure, they could show part of a screenshot and ask stuff like "what company developed this game?" and "what year was this game released?" because that's roughly what they have, but they'd need quite a different set of metadata for questions like "which of these images contain a group of at least two gnolls?" and "where in this image is the skeleton?".
The former is a fuckload more annoying than the latter to get through unless you already have encyclopaedic knowledge of gaming (personally, at least, I would prefer not to have to visit Wikipedia in order to log in to GOG, and that doesn't even include identifying the game), and the latter requires a fuckload of work to set up.