//preload images
var image1=new Image()
image1.src="images/tn_Web_Example1.jpg"

var image2=new Image()
image2.src="images/tn_Web_Example2.jpg"

var image3=new Image()
image3.src="images/tn_Web_Example3.jpg"

var image4=new Image()
image4.src="images/tn_Web_Example4.jpg"