The Museum Of New Zealand has released 30,000 images into the public domain, 17,000 of which are free to use commercially.
They say: …’But even better are the 17,000 images that downloadable for any use, any use at all. These images have no known copyright restrictions. Again it would be good if you attributed the original maker of the work, and link to the page on Collections Online so others can find it, but that isn’t mandatory.’
…’Over 14,000 images are available under a Creative Commons licence CC BY-NC-ND. If you aren’t familiar with Creative Commons it can look a little complicated, but what it means is you can use those images if attribute the image (we help you do that at each download page). You can’t make money from using the image, and you can’t change the image. Might sound a little restrictive but there is plenty you can still do, like use it in your homework, on your blog, print it and hang it on your wall…’