in their own projects for free. Pretty good deal, since honestly, art is probably the hardest thing to get.
Stock art isn't overly expensive per piece ($3-4 generally), but it adds up after a while. As Silent Legions is a Call of Cthulhu style game set in the real world as opposed to fantasy, some of the art isn't appropriate, but much of it would still work.
Artists include Earl Geier (sadly only that piece above), Joyce Maureira (who is really, really good), David Lewis Johnson (of Cromdar fame), Luigi Castellani (who has trouble with hands, but here is pretty decent), Miguel Santos, and Nikola Avramovic who is also quite good.