You may be familiar with Wikipedia. This is a major web-based encyclopedia project that anyone is allowed to contribute to. There is also a Wikimedia Commons site that provides pictures that are free to use. There are some great images of Niagara Falls on the site:
Wikimedia Commons is a media repository that is created and maintained not by paid-for artists, but by volunteers. Its name “Wikimedia Commons” is derived from that of the umbrella project “Wikimedia” managing all Wikimedia projects and from the plural noun “commons” as its contents are shared by different language versions and different kinds of Wikimedia projects. Thus it provides a central repository for freely licensed photographs, diagrams, animations, music, spoken text, video clips, and media of all sorts that are useful for any Wikimedia project…
Unlike traditional media repositories Wikimedia Commons is free. Everyone is allowed to copy, use and modify any files here freely as long the source and the authors are credited and as long you release your copies/improvements under the same freedom to others.
If you have some great picture sof Niagara Falls or any other location, you too can contribute!