<http://schema.org/primaryImageOfPage>
"http://media.treehugger.com/assets/images/2011/10/solar-greenhouse-geodesic-dome-finished-interior-photo.jpg"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/slideshows/green-food/build-a-geodesic-dome-solar-greenhouse-to-grow-your-own-food/page/18/>