‘An American academic is creating a searchable database of 12 million historical copyright-free images.
Kalev Leetaru has already uploaded 2.6 million pictures to Flickr, which are searchable thanks to tags that have been automatically added.
The photos and drawings are sourced from more than 600 million library book pages scanned in by the Internet Archive organisation.
The images have been difficult to access until now.
Mr Leetaru said digitisation projects had so far focused on words and ignored pictures.
"For all these years all the libraries have been digitising their books, but they have been putting them up as PDFs or text searchable works," he told the BBC.
"They have been focusing on the books as a collection of words. This inverts that."
Most of the images that are in the books are not in any of the art galleries of the world - the original copies have long ago been lost.”
The pictures range from 1500 to 1922, when copyright restrictions kick in.’