The National Gallery of Art aims to collect, conserve, and exhibit various works of art from around the world.
They have also adopted an open access policy for images of art that are presumed to be in the public domain. You can read more about their policy here.
“PD_worldart” , “PD_paintings” , “PD_sculptures”
The National Archives and Records Administration home page.
The NARA is the keeper of some of the most important records from the United States Federal Government. According to their site, most of their images are in the public domain and are therefore free to use. To read more about copyright information, scroll down the page to the “Copyright” section.
“PD_warfiles” , “PD_governmentfiles”
Cooper-Hewitt, Smithsonian Design Museum
Cooper-Hewitt is a museum focused on historic and contemporary design. It is the only museum in the United States dedicated solely to the topic of design.
Much of their content is not copyright restricted and aims to make its collections as accessible as possible. Here you can read more about their open source projects.
“PD_design” , “PD_clothing” , “PD_historicdecorations”
The Prelinger Archives is a large film collection in which all of its films are free to use by the public and are in the public domain.
Their section on “Rights” can be found here. Just scroll down until to see the section titled “Rights.”
“PD_usarmyfilm” , “PD_amateurfilm”
NASA on the Commons
The NASA-GRIN project has relocated to Flickr, where NASA’s open source images, film and video are available to use by the public. See their Profile on Flickr for more information about their project.
“PD_astronauts” , “PD_space” , “PD_historicalfilm
The J. Paul Getty Museum
This museum aims to conserve, interpret and exhibit significant pieces of art. Their research institute has also worked to digitize much of their collections and help their images be able to be used freely and without permission.
Some parts of The Getty’s website are under the Creative Commons license.
Also, The Getty Research institute holds rights to many digital images that are in the public domain. All such images (public domain) are free to be used, without permission under their Open Content project.