Put in a single player spawn in your map goto GENERAL IMFORMATION uncheck all ticks in gametype then you can test and take your screenshot In singleplayer,You can get some really good ones using the F4 key for 3rd person and use "NumPad Keys"
7 and 9 are zoom IN-OUT 4 and 6 Left-Right,8 and 9 Tilt Cam UP-Down.
You Can see how your maps look fron all angles this way too.
Hope I made that clear enough Ill Upload screen shots So You Can See What I Mean.Ill Post links later.
Oh Just remember to put the game types back to TDM Ect After.
Im Glad To SAY this dont work in multiplayer.