var rand_int = Math.floor(Math.random()*5); 
var photos = new Array(5) 
photos[0] = '<img src="images/image5.jpg" width="148" height="100" alt="" border="0" align="right">'; 
photos[1] = '<img src="images/image2.jpg" width="148" height="100" alt="" border="0" align="right">'; 
photos[2] = '<img src="images/image3.jpg" width="148" height="100" alt="" border="0" align="right">'; 
photos[3] = '<img src="images/image4.jpg" width="148" height="100" alt="" border="0" align="right">'; 
photos[4] = '<img src="images/image.jpg" width="148" height="100" alt="" border="0" align="right">'; 
document.write(photos[rand_int]); 