State by State copyright info: U.S. Copyright Office:
Copyright at Harvard Library Copyright.gov
Helping students understand "FAIR USE"? Look here
Famous cases help untangle the info.
Find images you can freely use in projects - learn how to create your own recordings .... tools!
12 Famous Art Museums that offer virtual tours. From Arts & Leisure Magazine
From Pure WOW: Virtual Art Museum tours for kids
My fav: 
Dr. Karl Kramer of Tucson, AZ.
He created the most amazing set of historical images, video and other media. Pick Apply them liberally throughout your teaching unit. Click on the image to see them all:
A HUGE thank you to Dr Kramer for allowing me to share these with you.
Share how folks in the past thought about the future - check out THESE photos!
Art teachers - what might your students imagine for their future?
Social Studies teachers - what has come true? How is it the same as the vision? How is it different?
Vocational Ed teachers - how might they improve a current product? Trace the path from historical imagination (of cars, for example) to todays reality.
Recently created, the Louve has now made their entire collection available digitally. While not quite like an in-person visit, these pieces of artwork - from textiles, painting, and drawing to sculptures, furniture, and objects - your students can enjoy the offerings of one of the world's premiere museums.
Something here for EVERY subject - because every subject has art.
The National Gallery of Art celebrates ALL of the U.S.
Here is their link to the Harlem Renaissance exhibit ... but wait! There's more...
Photographs of the Great War, Great Depression, ..until the end of the Century.
Use a photograph as a Q-focus to get students to ask great questions - follow up with the research process for sharing perspectives.
"Rising earth greets Apollo VIII astronauts as they come from behind the moon after
the lunar orbit insertion burn. Earth is about 5 degrees above the horizon."
By William Anders, December 29, 1968 National Archives and Records Administration,
Records of the U.S. Information Agency