<http://schema.org/image>
<http://cdn1.tnwcdn.com/wp-content/blogs.dir/1/files/2012/03/Highlighters-520x245.jpg>
<http://thenextweb.com/apps/2012/03/09/infocus-a-neat-web-app-that-lets-you-highlight-webpages-and-send-focused-links/>