Are you familiar with Geotagging? It is the process by which you can add GPS data to the properties of a photo.
Why would people wish to do such things? Well, think about it. When you travel on trips, you take lots of pictures. Perhaps you are in an area where the scenery looks the same from place to place, making it hard to later remember the locations of the sites that you visited.
Now, you can geotag your pictures, giving them data that can be decoded to give the exact location of the place that the picture was taken. You can use your own GPS data to do this, or you can actually import GPS data from Google Earth. By doing a flyover to your location in Google Earth, the software can actually figure out the exact location of your picture(s) based on your Google earth location.
The program to do this is called “Panorado Flyer.” It is free for personal or non-comercial use. Be sure to check it out and begin geotagging your pictures.