var imagenumber = 4 ;
var randomnumber = Math.random() ;
var rand1 = Math.round( (imagenumber-1) * randomnumber) + 1 ;
images = new Array
images[1] = "../images/itw_gag_center_image_3.jpg"
images[2] = "../images/itw_gag_center_image_4.jpg"
images[3] = "../images/itw_gag_center_image_6.jpg"
images[4] = "../images/itw_gag_center_image_7.jpg"
var image = images[rand1]