====== copyright free images ======
=== How to obtain copyright free images ===
  - Ask the author - often a quick email to the original author will help
  - [[https://www.nlm.nih.gov/hmd/ihm/index.html|NIH images from the history of medicine]]
  - [[http://phil.cdc.gov/phil/home.asp|Public Health Image Library]]
  - [[http://commons.wikimedia.org/wiki/Main_Page|Wikimedia Commons]]