The Dangers Of Glue
This is what happens to glue over the years. It turns brown and stains the surface of the photos, permanently damaging them, so please do not use glue on original photos.
The bottom photo was removed from an album. Unfortunately more damage may be caused by trying to remove photographs from older, historic albums than by leaving them intact.
If important or heirloom photographs must be attached in an album, use paper or plastic photo-corners.