<http://schema.org/thumbnailUrl>
<https://drscdn.500px.org/photo/16051649/w%3D160_h%3D160_s%3D1/396b720aebda6c5b429b82b8380eb0c7>
<https://marketplace.500px.com/photos/16051649/another-sunset-in-mexico-2-by-gerardo-aguilar>