If by backdrops you're referring to
skyboxes, there is a very useful and easy to use program called
Skies which you can download for free from
http://fpsfree.com/. A very handy tool, you simply need 6 images, which in this case can be .JPG's, that are then compiled together with the click of a button, and automatically saved into your skybox folder and ready to use 100% in
FPSC. You can even play around with your images within
Skies to make them brighter or darker, or play around with the light contrast to get the atmosphere of your liking.
Short of this, I'm not overly sure what you're asking if it's not in regards to skyboxes. Hope this helped though!
Cheers
Life would be much easier if I had the source code.