<http://schema.org/image_url>
"http://media.nola.com/politics/photo/sen-mary-landrieujpg-d1ba4fe1bc542dc1.jpg"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.nola.com/politics/index.ssf/2013/12/sen_landrieu_campaign_begins_a.html>