Concept Art
From WikiRaider
A Concept Art is a piece of art specially made during the early development of a video game like the Tomb Raider Games. It is intended to give the developers and designers a point of reference of how a level or scene might look and work in the completed game. Concept arts can be as simple as a comic-like sequence of images (like a Storyboard) to big size oil paintings.
There are several examples of official concept arts provided by Crystal Dynamics on our forums.[1]