Is it protected by copyright? Is it in the Public Domain?
A helpful guide from Cornell University: http://copyright.cornell.edu/resources/docs/copyright2014.pdf
The ALA Office for Information Technology Policy Slider Tool:
General Information on copyright and education:
Fair Use Checklist:
Exemptions for Instructors Web Tool:
TEACH Act Checklist:
Copyright-free Music & Photo Sources:
Search Flickr or Google Images with the Creative Commons filter
Creative Commons recommends these:
Search in YouTube. When the search is complete, you can apply filters. One of the filters is “Creative Commons” under Features.
Best practice for attributing CC content: