// Preload image - incase they are large images.
if(document.images){
  var main = new Image(); main.src = "images/Home/main7.jpg";
  var img1 = new Image(); img1.src = "images/Home/main7.jpg";
  var img2 = new Image(); img2.src = "images/heavylifting/main9.jpg";
  var img3 = new Image(); img3.src = "images/plant construction/main7.jpg";
  var img4 = new Image(); img4.src = "main4.jpg";
  var img5 = new Image(); img5.src = "images/Home/DSC_5486.jpg";
  var img6 = new Image(); img6.src = "images/Home/main8.jpg";
  var img17 = new Image(); img17.src = "images/Home/main9.jpg";
}

function change(imageName){
  if(document.images){ document['main'].src = eval(imageName + ".src"); }
}

function changeBack(){
  if(document.images){ document['main'].src = main.src; }
}