$(document).ready(function (){ 
var setupRandomImage = function (element){ 
var $element = $(element); 
var width = $element.width(); 
var height = $element.outerHeight(); 
var src = '/' + width + '/' + height + '?random&element=' + $element.prop('tagName'); 
$element.css('background-image', 'url(' + src + ')'); 
} 
; 
setupRandomImage('.intro-header'); 
setupRandomImage('footer'); 
} 
);