demo.js

var previews = new FilePreviews({debug: true});

var url = 'https://www.filepicker.io/api/file/WHOGzEmPRSGNYKyHRBWk';
var options = {
  size: {
    width: 100,
    height: 999,
  },
  metadata: ['ocr', 'exif']
};

previews.generate(url, options, function(err, result) {
  console.log(result);
});