var image1=new Image;
image1.src='images/banner_scow.jpg';
var image2=new Image;
image2.src='images/banner_scow_1.jpg';
var image3=new Image;
image3.src='images/banner_scow_2.jpg';
var image4=new Image;
image4.src='images/banner_scow_3.jpg';

function getRandomImage(low,high) {
	var x;
	x = Math.floor(Math.random()*(low,high));

switch (x){
case 0:
document.image.src=image1.src
document.image.alt = "Scows - Mary and Bill" 
break;
case 1:
document.image.src=image2.src 
document.image.alt = "Scows - Oliver" 
break;
case 2:
document.image.src=image3.src 
document.image.alt = "Scows - Oliver" 
break;
case 3:
document.image.src=image4.src 
document.image.alt = "Scows - Peter" 
break;
}
}