<http://schema.org/thumbnailUrl>
<https://drscdn.500px.org/photo/17615333/w%3D160_h%3D160_s%3D1/b96c51d1beeebe980cc284964ae5f7c9>
<https://marketplace.500px.com/photos/17615333/cloud-waves-at-sunset-by-alexandru-vlad>