All YouTube videos haveĀ four default images. They have standard formats : http://img.youtube.com/vi/video-id/0.jpg http://img.youtube.com/vi/video-id/1.jpg http://img.youtube.com/vi/video-id/2.jpg http://img.youtube.com/vi/video-id/3.jpg 0.jpg in the list is a full size image and rest of them are thumbnail images( 1.jpg, 2.jpg, 3.jpg). Also have some additional sizes but the availability of following images are depends on the video. http://img.youtube.com/vi/video-id/default.jpg http://img.youtube.com/vi/video-id/hqdefault.jpg -high…