This image is a work published by a facebook user using the Public setting, and is consequently free content.
The legal Terms of Use of facebook say: "When you publish content or information using the Public setting, it means that you are allowing everyone, including people off of Facebook, to access and use that information, and to associate it with you (i.e., your name and profile picture)." and "By "use" we mean use, run, copy, publicly perform or display, distribute, modify, translate, and create derivative works of." [1]
So, Public content on facebook is free, but content just shared with friends or groups is not free.
(If someone releases content under a free license they didn't own the copyright to in the first place, the license is not valid. Like with any other content published under a free license, this is the case with content published on facebook with a Public privacy setting.)
Subject to disclaimers.
Handy reference: Free_content says:
..."A free cultural work is one which has no significant legal restriction on people's freedom:
- to use the content and benefit from using it,
- to study the content and apply what is learned,
- to make and distribute copies of the content,
- to change and improve the content and distribute these derivative works.[2][3]
- ^ https://www.facebook.com/terms.php November 15, 2013 version, accessed Aug 2 2014.
- ^ "Definition of Free Cultural Works". Retrieved 8 December 2011.
- ^ Stallman, Richard (November 13, 2008). "Free Software and Free Manuals". Free Software Foundation. Retrieved March 22, 2009.