Failing to get Facebook screenshots via Casper

casper-screenshot-example.js

var casper = require("casper").create(),
  urls = [
    'https://www.facebook.com/ModernApartmentCommunity/',
    'https://www.facebook.com/ModernApartmentCommunity/reviews/'
    'http://modernmsg.com',
    'http://modernmsg.com/rewards'
  ],
  saveDir = 'shots'
 
casper.start();
 
casper.each(urls, function(self, url) {
  this.viewport(1024, 768);
  casper.thenOpen(url, function() {
    this.echo('Opening ' + url);
    //give some time for the page to load
    casper.wait(10000, function() {
      var ACfilename = saveDir + '/' + url.replace(/[^a-zA-Z0-9]/gi, '-').replace(/^https?-+/, '') + ".png";
      this.capture(ACfilename, {top: 0,left: 0,width: 1024, height: 768});
      this.echo('snapshot taken');
    });
  });
});
 
casper.run();