function changeImage(imagename){
	var images = new Array("image1", "image2", "image3", "image4", "image5", "image6", "image7");
	for (i=0;i<document.getElementsByTagName("div").length; i++)
		for (m=0;m<images.length; m++){
			if (document.getElementsByTagName("div").item(i).className == imagename){
				document.getElementsByTagName("div").item(i).style.display = "block";
			} else if(document.getElementsByTagName("div").item(i).className == images[m]){
				document.getElementsByTagName("div").item(i).style.display = "none";
			}	
		}

}