<http://schema.org/thumbnailUrl>
<https://drscdn.500px.org/photo/20946361/w%3D160_h%3D160_s%3D1/81e6df99a57973234cbabef18b86ea27>
<https://marketplace.500px.com/photos/20946361/abstract-traffic-princes-st-edinburgh-scotland-by-lisa-bettany>