The British Library has joined the Flickr Commons, a huge collection of historical photos and drawings from around the world. Even better these photos are drawing are free to use in your online and offline projects.
After a quick search, I came across this charming graphic from A Child’s Garden of Verses … Second edition by Robert Louis Stevenson. You can find artwork like this by visiting the The British Library on Flickr or the overall Flickr Commons. I think you’ll be pleasantly surprised by what you find there.