<http://schema.org/thumbnailUrl>
<https://drscdn.500px.org/photo/22280977/w%3D160_h%3D160_s%3D1/fe33a9542e919047c8a65a382dca8d5e>
<https://marketplace.500px.com/photos/22280977/down-by-the-river-by-peter-zajfrid>