var imagenumber = 5 ; 
var randomnumber = Math.random() ; 
var rand1 = Math.round( (imagenumber-1) * randomnumber) + 1 ; 
images = new Array 
images[1] = "img/spnos2.gif" 
images[2] = "img/spnos3.gif"
images[3] = "img/spnos4.gif"
images[4] = "img/spnos5.gif"
images[5] = "img/spnos6.gif"
var myimage = images[rand1] 
document.write('<img src="' + myimage + '", width="450" height="191" alt="Soleventi" border="0" />')