Get youtube video thumbnail

http://img.youtube.com/[VIDEO_ID]/[SIZE_PARAM].jpg
http://i.ytimg.com/[VIDEO_ID]/[SIZE_PARAM].jpg

Small thumbnail (120×90)

http://i.ytimg.com/vi/[VIDEO_ID]/1.jpg

http://i.ytimg.com/vi/[VIDEO_ID]/2.jpg

http://i.ytimg.com/vi/[VIDEO_ID]/3.jpg

Defaut size thumbnail (480×360) –

http://i.ytimg.com/vi/[VIDEO_ID]/0.jpg

Defaut

http://i.ytimg.com/vi/[VIDEO_ID]/default.jpg

Medium resolution

http://i.ytimg.com/vi/[VIDEO_ID]/mqdefault.jpg

Hight Resolution

http://img.youtube.com/vi/[VIDEO_ID]/hqdefault.jpg

Max resolution

http://i.ytimg.com/vi/[VIDEO_ID]/maxresdefault.jpg

Alternatively, you can use the YouTube API to get thumbnail images.

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