<http://schema.org/image_url>
"http://media.nola.com/tpphotos/photo/2011/05/-97bac9454f422896.jpg"^^<http://www.w3.org/2001/XMLSchema#string>
<http://photos.nola.com/4500/gallery/joplin_missouri_reeling_from_historic_tornado/index.html>