A photographic image, used to illustrate a news or other story, that is not recent but was taken at an earlier time.
there were only library pictures available at that point
the latest photograph is always preferable to a library picture
Example sentencesExamples
That plane is not a Gipsy Moth replica, it could have been a library picture taken earlier.
To try and tell a unique, individual story using a library picture can only reduce the impact of the story and sell the reader short.
Two days of hot summer weather and we'll be getting the usual warnings of global warming together with old BBC library pictures of the ice melting in the Antarctic.
I suppose that the paper has just one library picture of a generic mosquito to cover any story.
The pictures attached are library pictures of a car we sympathetically restored two years ago.