What the map looks like is determined entirely by what map image the mapmaker used... which could be any image. If they tweaked it properly you could play on a photograph of a duck. Most of the screens are using the images the random map generator uses. But the maps included with the game have custom images.
edit: wrong reply to apparently, for the guy with the map question below this
The_Demon
T joined
This member has provided no bio about themself...