<http://schema.org/thumbnailUrl>
<http://i1.wp.com/www.gottabemobile.com/wp-content/uploads/2014/03/google-docs-and-sheets-add-ons.jpg?fit=150%2C150>
<http://www.gottabemobile.com/2014/03/15/how-to-use-google-drives-new-add-ons-in-google-docs-and-spreadsheets/>