The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies. These are not necessarily in the public domain.
The SOHO (ESA & NASA) joint project implies that all materials created by its probe are copyrighted and require permission for commercial non-educational use. [2]
Uploaded a work by NASA from https://www.facebook.com/nasamarshallcenter/posts/pfbid0246Ph8XA4mR3i3mbALfNovXZ2CwbBQhPPnzpzoDgjjXih3QAsgt4tSLz75dhSzutcl with UploadWizard