According to the Library of Congress, "copyright refers to the author's (creators of all sorts such as writers, photographers, artists, film producers, composers, and programmers) exclusive right to reproduce, prepare derivative works, distribute copies, and publicly perform and display their works."
Finding Media That is Okay To Use
Almost everything is copyrighted and requires permission from its author to use. There are, however, some exceptions:
"Specially-licensed" - There is a lot of media that has been made available for anyone to use, waiving the need to obtain direct permission from the author. For example, a very common license is an "Attribution" license, meaning that you can use the media for any purpose as long as you give credit to the creator somewhere in your work. The non-profit organization Creative Commons offers a variety of attribution licenses that creators apply to their work to make available for public use. Learn more about Creative Commons licensing. Search for works with a Creative Commons license.