Victorian era framed photo or painting hangers for the wall? They hooked on ledges and held the wire on the back of the frame, so I have heard. Cool finds! Sub
I have a Victorian house and those type of picture hooks are found throughout.
In our home, there is a trim about 8 to 10 inches below the crown moulding that has a slot on the top. The hook is set into the slot and pictures (and such) are hung on braided wire...this eliminates driving nails into the older lath and plaster.
Look near the bottom of the picture and you can see that the hooks are visible. this should give you an idea...Old photo when I bought the house...solid redwood walls...absolutely no termites or rot...