<http://schema.org/primaryImageOfPage>
"http://media.treehugger.com/assets/images/2012/05/solar-water-heater-diy-2.jpg"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/slideshows/solar-technology/how-make-solar-water-heater-water-bottles-20/page/2/>