This first picture is probably one of my favorite ever. The second one ranks right up there as well. As far as I know they were created digitally and probably aren't available for purchase anywhere, but I've never really checked. You can see the author's name at the bottom and I think he has some other stuff as well. The third picture is well done too, but it doesn't stun me quite like the first two do.
If I remember correctly, the first one is called Dark Angel, second one is depicting pouring the plagues into the Euphrates River (not sure the name), and the third one is called Lilith.