<http://schema.org/thumbnailUrl>
<http://cdn1.tnwcdn.com/wp-content/blogs.dir/1/files/2011/09/Photography-520x245.jpg>
<http://thenextweb.com/apps/2011/09/12/photo-academy-an-all-in-one-photography-guide-on-your-iphone/photo-academy-1/>