Getting YouTube Thumbnail By link

http://img.youtube.com/vi/ID/0.jpg (480 x 360 px, jpg.)

http://img.youtube.com/vi/ID/1.jpg (120 x 90 px, jpg)

http://img.youtube.com/vi/ID/2.jpg (120 x 90 px, jpg.)

http://img.youtube.com/vi/ID/3.jpg (120 x 90 px, jpg.)


http://img.youtube.com/vi/ID/default.jpg
(Thumbnail low resolution, the same as 0.jpg.
120 x 90 px, jpg.)

http://img.youtube.com/vi/ID/mqdefault.jpg
(Thumbnail in medium resolutionlow, the same as 0.jpg.
320 x 180 px, jpg.)

http://img.youtube.com/vi/ID/hqdefault.jpg
(Thumbnail in medium resolutionhigh, the same as 0.jpg.
480 x 360 px, jpg.)

http://img.youtube.com/vi/ID/sddefault.jpg
(Thumbnail in medium-high resolution, the same as 0.jpg.
640 x 480 px, jpg.)


http://img.youtube.com/vi/ID/maxresdefault.jpg

(Thumbnail in high resolution, the same as 0.jpg.
Variable size (1920 x 1080 px / 1280 x 720 px ...), jpg.)