Photos from generations past are one of a kind, and aren't always printed on archival paper. They can become wrinkled or curled over time. If you have an old photo you want to preserve, try to flatten the curled edges.
Fold a sheet of wax paper over the picture to protect it from sticking, then insert it into the middle of a thick book. Place the book on a bookshelf where the books are tight. After several weeks, the photo should be flat again.
Place the photo on an ironing board, place a towel on the photo and press with the iron on the lowest setting. Check the picture often to ensure it isn't being damaged. Continue the process until the picture is flattened.
Flatten the photo temporarily in a scan bed. If you don't have a scanner, visit an office supply store or photo lab. Now you'll have a digital copy of your photo and you can even restore the color, repair scratches and print duplicate copies.