So, there's been enough shelling of various gothic landscapes in our world that we have some references...
From World War One, a collection of public domain photographs.
Death and DestructionIf you back up a few levels on that site, there are many other inspirational photos for Imperial Guard, locations, etc.
Here is a collection of hundreds of posters issued by the Us gub'mint, for World War Two. Photoshop 'em, resize 'em, and plaster them over your terrain.
Propaganda!Finally, a small gallery of [colour] world war two pictures. Take a look at the colors of the war-torn terrain in these photos.
[colour]!--Brian, pushing the inspiration button again. :D