The British Library has recently released over a million images to the public, following a digitisation project with Microsoft. The images can be found through Flickr, and the BL is keen to get the public to find new ways to 'curate' and organise the vast collection of 17th-19th century scans.
Much more here.
Access the full collection here on Flickr. I find it best to explore it through the albums already set up.