The Museum of New Zealand Te Papa Tongarewa in Wellington has made over 30,000 images of works from its collection available for free download. Over 14,000 of these are released under a Creative Commons CC BY-NC-ND license that requires attribution and prohibits any commercial use or the making of derivatives. The remaining 17,000 images have no known copyright restrictions, and are available for any use.
Te Papa is New Zealand’s national museum, and its collections include art as well as history, natural history, and Maori and Pacific cultures. You can read more about this image initiative on Te Papa’s blog, or begin exploring the Collections Online.