var imagenumber = 5 ;

var randomnumber = Math.random() ;

var rand1 = Math.round( (imagenumber-1) * randomnumber) + 1 ;

images = new Array

images[1] = "images/random/01.jpg"

images[2] = "images/random/02.jpg"

images[3] = "images/random/03.jpg"

images[4] = "images/random/04.jpg"

images[5] = "images/random/05.jpg"

var image = images[rand1]