Other portals (some subject-specific)
Also of interest:
FlickrStorm another Flickr search engine which returns more, related images
Public Domain Images
Pulic Domain images are able to be freely used by anyone without first gaining permission.
CopyrightFriendly.com is a website with a list of links to lots of other public domain and free websites. It is set up with the headings:
Other Public Domain images can be found at:
All images from the Picture Australia website may be used for research or educational purposes, in accordance with the Copyright Act 1968 (Cth). If you intend to publish the images in print or online, other than as permitted by this Conditions of Use statement, you will need to get permission from the contributingagency