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]
{{PD-USGov-NASA}} Satellite image of Barbados September 2002. Cropped image, original from NASA's Visible Earth http://visibleearth.nasa.gov/cgi-bin/viewrecord?21888