function get_random() {
  // Make sure that random()*X) has the correct number.
  var ranNum= Math.floor(Math.random()*3);
  return ranNum;
}
var whichImg=get_random();
function show_image() {
  // Make sure that Array(X) has the number of images
  var img=new Array(3)
  img[0]="http://www.pvcc.edu/img/bg/sum_home_8.jpg";
  img[1]="http://www.pvcc.edu/img/bg/sum_home_18.jpg";
  img[2]="http://www.pvcc.edu/img/bg/sum_home_20.jpg";
  // Here the actual displaying of the image is taking place.
  document.write("<div id='righttop' style='background:url(");
  document.write(img[whichImg]);
  document.write(") #ffffff no-repeat;'>");
}