<http://schema.org/thumbnailUrl>
<https://drscdn.500px.org/photo/16743595/w%3D160_h%3D160_s%3D1/04ca9f3cba437fe92721be3abc1b5cd1>
<https://marketplace.500px.com/photos/16743595/bridge-and-sky-by-chihiro-imahashi>