If you have an antique picture frame, don’t throw it away! Take it to your local picture framer to see what can be done to restore it. It may be the case that it is too damaged but it is best to ask your framer first.
The most common problem we encounter with old frames are the corner joints. In past times the corners of frames were put together with nails and glue. Once time has done with the glue the corners are usually only hanging together with a nail or two and a bit of hope!
What the framer can do is take the frame apart, clean up the corners by slicing off a fraction or more if required and re-pinning the frame together.
If the corners have been damaged considerably the framer will need make a new cut deeper into the lengths of moulding and the frame consequentially will get smaller. This might not cause a problem if there was enough wriggle-room to begin with. (Wriggle-room being the difference between the size of the glass and mount and the inner rebate of the moulding)
Whatever the case, old and antique frames can be re-used for smaller pictures and as I outline above be given a new lease of life in its original form. Don’t throw them away, as in many cases they are not only beautiful mouldings but also irreplaceable.