My backdrops are split into two different types, but both use the end result. I either take the photos myself using a cheap DSLR or use a free image from the internet. As I mostly wargame Bolt Action and Normandy my local Gloucestershire countryside is perfect, but I need the internet for further afield.
Once I have my image depending on size I either print it or get it developed online as a panoramic picture (rough cost is £20 for 800x30). Don’t forget that these pictures can be used again and again for future photo shoots and are well worth the money and super realistic.
Onto my setup. I use either a £20 mini-Amazon backdrop holder, clothes pegs or blu tac to hold up my backdrop.
The basic principle of getting a backdrop correct is make sure you get the foreground to blend into the background as seamless as possible. The easiest way to do this is my lowering the backdrop a cm behind your base board thus starting to create an illusion of being natural. You can then further add to this illusion by adding hedges, walls etc. at the rear of the board between the subject and backdrop covering the obvious join up. Hope this all makes sense?
A few pictures of my backdrops and work.