The re-use of images, audio/video files and other media for educational purposes (not including print or electronic publication of any kind) is generally considered acceptable under the terms of fair use. If you wish to publish media online (i.e. YouTube) or in print, even if for educational purposes, you will first need to determine whether or not the image is protected by copyright, then find out how to get copyright clearance (Images: A Guide to Finding, 2014).
The University of Cincinnati Libraries sums up citing images well in its Library "Media" research guide by providing the following information:
Documenting sources for images can be challenging, especially with the variety of new electronic resources now available. Many different style manuals exist. Listed below are several writing style manuals that may be consulted along with examples. Always ask your class instructor for the style appropriate for the course.
The basic information you will need:
If you found the image in a book, you will also need the author, title, publisher information, date, page, and figure or plate number of the reproduction. If you found the image online, you will need an access date, the web site address (URL), and, in some cases, an image ID number (Media, 2014).
Additionally, you may need to obtain permission to publish images found in licensed Library databases or digital collections (i.e. The Library of Congress, College of Charleston Digital Collections, Artstor). In many cases, you will need to write to the institution that owns the physical image and request permission to publish it. There is often a fee associated with acquiring permission (Images: A Guide to Finding, 2014).
Critical Commons is a public media archive and fair use advocacy network that supports the transformative reuse of media in scholarly and creative contexts. It is an online platform for viewing, tagging, sharing, annotating curating and spreading media. Critical Commons goal is to build open, informed communities around media-based research, teaching, learning and creativity. Critical Commons is not affiliated in any way with Creative Commons.
Source: About Critical Commons
Disney Parody explanation of Copyright Law and Fair Use
"Professor Eric Faden of Bucknell University provides this humorous, yet informative, review of copyright principles delivered through the words of the very folks we can thank for nearly endless copyright terms" ("A Fair(y) Use Tale," 2007).
Permanent URL: http://cyberlaw.stanford.edu/documentary-film-program/film/a-fair-y-use-tale
Creative Commons is a nonprofit corporation dedicated to making it easier for people to share and build upon the work of others, consistent with the rules of copyright.
They provide free licenses and other legal tools to mark creative work with the freedom the creator wants it to carry, so others can share, remix, use commercially, or any combination thereof.
The study, Recut, Reframe, Recycle: Quoting Copyrighted Material in User-Generated Video, by Center director Pat Aufderheide and Peter Jaszi, co-director of the law school’s Program on Information Justice and Intellectual Property, shows that many uses of copyrighted material in today’s online videos are eligible for fair use consideration. The study points to a wide variety of practices—satire, parody, negative and positive commentary, discussion-triggers, illustration, diaries, archiving and of course, pastiche or collage (remixes and mashups)—all of which could be legal in some circumstances.