<http://schema.org/image>
<http://rack.2.mshcdn.com/media/ZgkyMDEyLzEyLzA0Lzc2LzIwZnJlZXNvY2lhLmFaTC5qcGcKcAl0aHVtYgkxMjAweDYyNyMKZQlqcGc/67104a69/717/20-free-social-media-icon-sets-for-a-more-shareable-website-00cf6ac5f4.jpg>
<http://mashable.com/2010/11/10/free-social-media-icons/>