If you are lucky enough to actually be in possession of original photos of your ancestors:
1. Digitally back up your photos. This makes it easy to share and to preserve them in case the original is damaged in any way. Scanning your photos is the best way (be sure to scan at the highest quality). At the very least, make color photocopies.
2. Store original photos properly. Keep originals away from light, heat, and humidity.
3. Make sure that any materials/papers that come in contact with your photos are acid-free and lignen-free.
4. If you are planning to mount your photos in an album, use photo corners to hold pictures in place on acid free cardstock and place in a protective sheet cover. Make sure that the album itself is acid-free also.
5. Never glue the original photo to a page or glue anything on the photo. All of the scrapbook pages I post have digital copies of old photos that I have printed out to enjoy and play with.
6. Print out and enjoy those wonderful digital copies so that your children and grandchildren can come to know their ancestors!