Fair use
From The Glossary of Digital Photography
Part of the US copyright law that allows the free use of intellectual property, such as images, without the copyright holder's permission and without infringing the copyright. Other countries have similar provisions under different names. There are only certain conditions under which this is allowed: criticism, journalism, research, scholarship, and teaching. The amount of the work used is also a factor considered when determining if a use is fair use as defined under the law. With images, for example, an image of Canada might be used freely and without permission if it appeared in an article that was about the image, but probably not if the article were just about Canada. This area of the law is extremely complex and an intellectual property attorney should be consulted when necessary before attempting to exercise fair use. Fair use is one of the most misunderstood areas of copyright law.
