In conjunction with Comic-Con, DC sponsored an art show in the Gas Lamp district of San Diego with the theme "Darkness & Light: Art Inspired by Heroes & Villains, Hope & Heroism". This was to raise money for Save the Children, International Rescue Committee and Mercy Corps. Nathan Sawaya was among the featured artists. I assume that these are his work, though the article I found did not give specific attributions to the different artists.
I found some more pics. The Superman and Green Lantern are definitely Nathan Sawaya - He made those last year and I featured them here.