Personally, I think it's concept art.
I can tell you it is legitimate as it was on the PCG DVD this month. They would be getting sued if they weren't real, and they aren't so I guess they are. PCG don't just pick any old screenshots off the net, they contact the developers (in this case Ensemble) and verify that they are real.
They are listed on Ensemble Studios' website as
Actual in-game screenshot
An example: http://www.ensemblestudios.com/Age3SS3.html
age of gun powder? meh, seems like a good idea
I take what n0e says way too seriously
50 XP
25th August 2003
0 Uploads
4,300 Posts
0 Threads
LOOKS KICKASS i went now :(
Its comng out 7/15/05:sillyme:
wow! looks amazing!