Facebook Thumbnail Full

Hi all. Can some tell me please how to make my sites FB thumbnail full on wall?? Something like here http://www.facebook.com/HipHopDX . I added a code to my site from http://www.wpbeginner.com/wp-themes/how-to-avoid-no-thumbnail-issue-while-sharing-post-on-facebook but its not showing the full picture from my site. Please help