function imageSwap() {
  var image = document.getElementById("imageHolder");
  var strPanoSrc  = "images/panorama.jpg";
  var strChartSrc = "images/chart.jpg";

  if (image.name == "chart") {
     image.setAttribute("src",strPanoSrc);
     image.setAttribute("name","panorama");
    } else {
     image.setAttribute("src",strChartSrc);
     image.setAttribute("name","chart");
    }
}