With the proliferation of cheap stock photo and image resources available, it’s easy to forget about the granddaddy of all collectors – governments. With 1,000,000+ archival images, the British Library is one of the best – it’s a remarkable cache of art and reference. All usable without restrictions.
Other worthy resources include:
> Wikimedia Commons
> Book Images Archive
> US Government Photos & Images collections
> Fickr Commons
> NYPL Digital collection
> Cornell University Library of the Fantastic