When it comes to making convincing photo backdrops, two people who stand out for me are Steve Flanigan (Louisville & Wadley Southern, above) and Tom Johnson (Logansport & Indiana Northern). These two have really nailed it; my own attempts at using photos for backdrops pale in comparison.
With their permission, I've posted photos and info about how they make their backdrops on my blog. Steve's work can be seen at http://cprailmmsub.blogspot.ca/2012/03/backdrop-artistry-of-steve-flanigan.html
Tom's work can be seen at
http://cprailmmsub.blogspot.ca/2012/03/more-backdrop-artistry-tom-johnsons.html
John Longhurst, Winnipeg