How to download Youtube Thumbnail ?

[mjk200]

please let me know how i can download youtube thumbnail without any website ?

[anon]

https://$HOST/vi/$VIDEO_ID/$SIZE.jpg


$HOST is one of

i.ytimg.com
img.youtube.com
ytimg.googleusercontent.com

$VIDEO_ID is the video's 11-character identifier.

$SIZE is one of

default
hqdefault
mqdefault
sddefault
maxresdefault

Not all sizes may be available.