The last time we saw images circulating regarding Left 4 Dead 3 it was from a visit to the Valve offices, something that while not easy, could be faked. This time around, thanks to some hunting by part of NeoGAF, today we've discovered some files linked to the title and these come straight from an official Valve video.
Drawn by Andrea Wicklund, illustrator at Valve, this Lobster Hunter painting was sped up and released for fans to view. Meant to help the creative process and give people some insight into how artists do there work, the video was just posted by Valve today. Not only is there a L4D3 folder, but when she mouses over it, it displays last modified as July 31st 2012. Even earlier than that, the concept art image files she blows over were last modified June 12th 2012.
The images can be seen at full size here.
This is only further verification that Left 3 Dead 3 is in fact, in development. The question is, when will any of this finally see the light of day? Valve time is a lot slower than real time.