An American academic is creating a massive, copyright-free database of 12 million historical images on Flickr.

Kalev Leetaru has already uploaded 2.6 million images, all dating from 1500 to 1922, when copyright restrictions go into effect, reports the BBC. His Internet Archive Book Images is fully searchable because each image has been tagged automatically with related text

"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," said Leetaru. While libraries have long been digitizing books, many have focused on text, creating PDFs or text searchable works, and ignoring images.

Leetaru developed software to save images in books as Jpegs and capture captions and surrounding texts in order to categorize the images. His project came out of research at Georgetown University in Washington ,DC, where he had a fellowship sponsored by Yahoo, the owner of photo-sharing service Flickr.