Do you need to find pictures to use in your classroom, but you are concerned about copyright? You need to check out Flickr Commons. I use Flickr to post pictures (My public Flickr PhotoStream). Flickr Commons take photos from libraries (like the Library of Congress) and posts them online for user to view and use. Most of the photos are copyright free which gives you the ability to download then and use them in classroom projects. Most of the photos are historic, so they would be great for Social Studies lessons.
The images below are from Flickr Commons. Click on the photos to see them in a slideshow format.
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