<http://schema.org/image>
<http://rack.1.mshcdn.com/media/ZgkyMDEyLzEyLzA0LzZhL2hvd3RvbGF1bmNoLmIyMC5qcGcKcAl0aHVtYgkxMjAweDYyNyMKZQlqcGc/bf9071f4/725/how-to-launch-a-successful-twitter-contest-d9bee68496.jpg>
<http://mashable.com/2010/12/29/how-to-twitter-contest/>