// Build array from n 
(function(){

  var images = [
    "/media/happathrenna/ny/Draumastjarna_100.png",
    "/media/happathrenna/ny/Heillastjarna_100.png",
    "/media/happathrenna/ny/Lukkustjarna_100.png",
    "/media/happathrenna/ny/Oskastjarna_100.png"
  ];
  var n = Math.round(Math.random() * (images.length-1));
  document.write('<img src="'+images[n]+'" alt="Happaþrenna" />');

})();