Hm here's some Easy Example.
This is the Texture of my Autorifle ( not my best work, in fact its more booring than awesome and im not really finished on this Texture ).
MS-Paint Concept ( Handpixeled ) :
The Texture that's showed ingame :
The Bump and Normal Maps were postet earlyer this Thread.
I like to work like that, cause i can use the Mask's i make from the concept, for the Bump, Gloss and Glow Maps too ( and its fitting perfect to the Texture then )
Such MS-Paint concept-Texture can also be used, to get some picture of what the Texture could look on a map object.
Like in this GTK shot here :
The Texture's used on that shot are MS-Paint Concepts.
As u can see, u can use it to get a view of what the Texture's should look like when they're finished.
*Edit* btw. i found some shot of that tunnel with finished Textures :
