City Store

I use gimp but I wonder what kind of technique do you use to obtain  such a fantastic and realistic light effect.
Please tell me :3  I suppose you use levels of course to make some part more dark and to enlighten the source of light, but how?

Hey Cisti, check out this vid: [link] starting at the 1:27:40 mark.

Thanks Bogieman....

Great map Cisti!