Thanks, gentlemen.
The wall and ground textures in the second pic are straight from the game (well the ground texture is what I started with before I made the weird perspective for the backdrop) and the sky *is* the back_north2.png image.
I thought about adding plants and rubbish and other stuff, but this was just the first attempt.
Also, I was thinking of only adding things that would be seen in the 3D view, so until I do some overlays...
I'm not very happy with the door - the resolution of the starting image is so low that it doesn't translate well. I guess that mean I'll be making new doors.
I might also construct some doors that open.
I've already figured out how to do the graphics, I just need the time.