get thumbnail images for youtube videos
$ npm install --save youtube-thumbnailvar youtubeThumbnail = require('youtube-thumbnail');
var thumbnail = youtubeThumbnail('https://www.youtube.com/watch?v=9bZkp7q19f0');
console.log(thumbnail);
// => { default: { url: 'http://img.youtube.com/vi/9bZkp7q19f0/default.jpg', ...$ npm install --global youtube-thumbnail$ youtube-thumbnail --help
  Example
    youtube-thumbnail https://www.youtube.com/watch?v=9bZkp7q19f0
       =>  http://img.youtube.com/vi/9bZkp7q19f0/default.jpg
    youtube-thumbnail https://www.youtube.com/watch?v=9bZkp7q19f0 --high --open
       =>  http://img.youtube.com/vi/9bZkp7q19f0/hqdefault.jpg
  Options
    --open
          opens the thumbnail image in your browser
    --medium
          returns the medium resolution thumbnail
    --high
          returns the high resolution thumbnailMIT © Matias Singers