function randomImage() {
var headImages = new Array(
'http://astro.nuigalway.ie/images/topbarimg/topbarimg01.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg02.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg03.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg04.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg05.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg06.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg07.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg08.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg09.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg10.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg11.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg12.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg13.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg14.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg15.jpg',
'http://astro.nuigalway.ie/images/topbarimg/topbarimg16.jpg'/* Make sure there is no comma at the end of the last image listed */
);

/* All above images should be 1000px wide and 110px in height.  Please note that the logo image will overlay the leftmost 300px (approx.) */

var max = headImages.length;
var num = Math.floor((Math.random() * max));
if (document.getElementById) {
  var headerImageDiv = document.getElementById('logoimage');
  if (headerImageDiv) {
    headerImageDiv.style.backgroundImage = "url(" + headImages[num] + ")";
  }
}
return;
}