We have released over a million images onto Flickr Commons for anyone to use, remix and repurpose. These images were taken from the pages of 17th, 18th and 19th century books digitised by Microsoft who then generously gifted the scanned images to us, allowing us to release them back into the Public Domain. The images themselves cover a startling mix of subjects: There are maps, geological diagrams, beautiful illustrations, comical satire, illuminated and decorative letters, colourful illustrations, landscapes, wall-paintings and so much more that even we are not aware of.
Okay but to clarify, the British Library did not put 1,000,000 Images into the Public Domain. The British Library digitized 1,000,000 public domain images.
These images were already public domain. Copyright expires 70 years after the death of the author. Once copyright expires, the creative work automatically becomes public domain, free to remix and reuse.
The British Library did not grant us the right to use these images. It made images we already had the right to use more easily accessible.