Keep Organized with a Personal Collection of Backdrop Photos
Strobist suggests keeping a personal catalog of the locations you've shot, and it's not terribly difficult to do. Start by taking a picture of the location without anyone or anything in front of it. Write down the address or, even better, tag the picture with GPS coordinates. Once you've done that, you can easily pop the pictures into a specific folder and even tag them on a site like Google Maps so you can see all your locations at once.
