<http://schema.org/image_url>
"http://media.pennlive.com/patriot-news/photo/2013/12/-8c89c6aa8130908f.jpg"^^<http://www.w3.org/2001/XMLSchema#string>
<http://photos.pennlive.com/4503/gallery/supersizing_healthcare_pinnaclehealth_system/index.html>