PIXABAY

• https://en.wikipedia.org/wiki/Pixabay
• Pixabay.com is an international, copyleft and free-to-use website for sharing photos, illustrations, vector graphics, and film footage.
  Launched: 24 November 2010; 9 years ago
  Owner: Hans Braxmeier & Simon Steinberger GbR
  Created by: Hans Braxmeier, Simon Steinberger
•  As of November 2017, Pixabay offers over 1,188,454 free photos, illustrations, and vectors and videos.
• Images and videos are released under the Pixabay License and may be used freely for almost any purpose - even commercially. Attribution is appreciated, but not required.
• https://pixabay.com/blog/posts/pixabay-license-what-is-allowed-and-what-is-not--4/
• https://pixabay.com/blog/topics/freebies-5/