<http://schema.org/thumbnailUrl>
<https://drscdn.500px.org/photo/22015141/w%3D160_h%3D160_s%3D1/5b4c8b51e5fcba03b3a1d5a9211940d7>
<https://marketplace.500px.com/photos/22015141/snowy-day-by-csilla-zelko>