It's from GDC

by Beorn , <End of Failed Timeline>, Friday, April 19, 2013, 09:35 (4037 days ago) @ breitzen

Not new. But still Freaking awesome. I think it's in DBO's image gallery. Pretty much all official concept art is over there so maybe you'll find some more nuggets of awesome sauce concept art!

It is indeed in the DBO image gallery! (I love that we can link directly to a specific piece). That particular artwork was part of the GDC presentation, which is definitely worth watching if you have the time.