img = new Array(35);
for (i=1; i<=35; i++) {
  img[i] = new Image()
  img[i].src="../images/gallery/image" + i + "-thumb.gif"
  img[i].alt=""
}

function showImage(num) {
  var imagediv = document.getElementById('galleryimage')
  imagediv.innerHTML='<img src="../images/gallery/image'+num+'-thumb.gif" alt=""/>'
}