Intended to protect the creative output of authors and other artists, copyright is an evolving acknowledgement of ownership. As new methods of expression are developed, and new ways to transmit information grow in acceptance, determining what can be copyrighted and by whom is no longer as straightforward as it was at the doctrine's inception, when it was applied only to "maps, charts, and books."
A full discussion of copyright is beyond the scope of this guide, but it should be noted that simply because you can download an image does not mean you are free to use it without limitation; the object itself may have no copyright protection, but its image may be licensed by an institution or photographer. Generally speaking, fair use exceptions are made for certain purposes, including academic research, but it is the user's responsibility to understand any potential copyright issues.
