<http://schema.org/thumbnailUrl>
<https://drscdn.500px.org/photo/22897467/w%3D160_h%3D160_s%3D1/82d68e2677d92cb78e8dc364c25da9e1>
<https://marketplace.500px.com/photos/22897467/fog-flow-at-sunrise-by-marc-crumpler>