Once a bit of a fringe cause, labelling online images for re-use and sharing (see Creative Commons) has gained some high-level impetus in recent years. Major art galleries and museums around the world have been releasing millions of images and encouraging audience engagement. Amsterdam's Rijksmuseum actually encourages users to re-mix and alter their high resolution artworks. Google's "Art Project" aggregates high resolution images of great art from many of the world's leading institutions. The common creative heritage of humanity, made accessible for anyone with an internet connection...
Old Pictures, Free at Last
Plenty of free pics online, but quality is far less common. For flashes of colour amidst the dross, try New Old Stock, Unsplash, British Library on Flickr, NASA on Flickr, the Rijksmuseum and the Google Art Project. Try also Agence Eureka and Bibliodyssey.
