From Qedoc

• Public Domain:
  • PD-gutenberg|Public Domain image obtained from the Project Gutenberg (PD-gutenberg)
  • PD-user|Public Domain - released into public domain by the author (PD-user)
  • PD-USgov|Public Domain - authored by the U.S. government (PD-USgov)
  • PD-NASA|Public Domain - authored by NASA (PD-NASA)
  • PD-old|Public Domain - copyright has expired (PD-old)
• Creative Commons:
  • CC-BY|Creative Commons Attribution (CC-BY)
  • CC-BY-SA|Creative Commons Attribution ShareAlike (CC-BY-SA)
  • CC-BY-NC|Creative Commons Attribution NonCommercial (CC-BY-NC)
  • CC-BY-NC-SA|Creative Commons Attribution NonCommercial ShareAlike (CC-BY-NC-SA)
• Other
  • GFDL|GNU Free Documentation License (GFDL)
  • LGPL|GNU Lesser General Public License (LGPL)
  • Copyrighted|Copyrighted - All Rights Reserved.
  • Screenshot|Screenshot - copyrighted.