Pictures like this take up an enormous amount of hard-drive. In order to get a clear, sharp picture out of a small portion of the picture (see cropped image below) you have to scan the picture at a high resolution and at least double it's original size. This makes for a huge file - but if it's a picture that's important to you and you really want to restore it - you may decide it's worth the space and effort.

I have done this with some pictures and they still didn't come out as clear as I had hoped. I think it has to do with the quality of the original picture and the extent of fading that has taken place over the years. There is a limit to what you can do with a picture that is badly faded or poor quality to begin with. See Miltead Teachers and the links on that page to the individual teachers (ie: Miss Florence Caldwell). That picture was taken from a newspaper. Not having the original picture made it very difficult to get a good clear picture of the teachers, but I tried! :)