<http://schema.org/thumbnailUrl>
<https://drscdn.500px.org/photo/21067679/w%3D160_h%3D160_s%3D1/25f800f85357bcb33d5a8f270c6a602b>
<https://marketplace.500px.com/photos/21067679/the-rose-iii-by-erik-anderson>