flickr-hacky-download.js

var photos = document.getElementsByClassName('photo-list-photo-view');
var photos_length = photos.length;
for ( var i = 0; i < photos_length; i++ ) {
  var photo = photos[i];

  var style_bg_image = photo.style.backgroundImage;
  var url = 'https:' + style_bg_image.replace('url(','').replace(')','');
      url = url.replace('"', '');
      url = url.replace('"', '');

  console.log(url);
}