Anyone who loves old photos and history is now indebted to an academic who's been busy sharing his passion, and his knowledge of coding, to publish millions of public copyrighted images on the photo sharing site Flickr.

Kalev Leetaru wrote a program that is helping take photos from public domain books in the Internet Archive and giving them their own individual Flickr page. Leetaru is research fellow at Georgetown University in Washington, D.C.

The books had been scanned for online access using an optical character recognition program and that program discarded the photos in the process.

Leetaru's code is bringing them back to life. So far the effort has resulted in 2.6 million images getting onto Flickr. He's hoping to get 12 million historic images up online as part of a service called "Internet Archive Book Images".

The images run the gamut from portraits to buildings to machinery and even include shots of sewing machines and musical score sheets. The Jpeg picture format images include text from the book before and after the image, as well as information about the book it came from.

In a media interview Leetaru said the books had been viewed as just a collection of words and his service respects the photo aspect of the tomes.

"This inverts that. Stretching half a millennia, it's amazing to see the total range of images and how the portrayals of things have changed over time. 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," he said.

Flickr users can search the growing catalog and use just one single search term to access photos as each image page offers text.

He's even grabbing illustrated print advertisement as part of the image recovery.

 "I think one of the greatest things people will do is time travel through the images," said Leetaru.

He's hoping that the photo preservation effort is something libraries worldwide decide to do as well.

"Any library could repeat this process. It's actually my hope, that libraries around the world run this same process of their digitized books to constantly expand this universe of images," he said.

Robert Miller, global director of books for the Internet Archive, wrote in a blog post there are about 14 million potential images that can be shared through Leetaru's efforts.

"This way of discovering and reading a book will help transform our medical heritage collection as it goes up online. This is a big step forward and will bring digitized book collections to new audiences," said Dr. Simon Chaplin, head of the Wellcome Library, as quoted by Miller in the blog post.