<http://schema.org/thumbnailUrl>
<https://drscdn.500px.org/photo/22335653/w%3D160_h%3D160_s%3D1/7816b6aa50d9743113477352dc980351>
<https://marketplace.500px.com/photos/22335653/snowfall-deep-river-on-by-jean-francois-thibeault>