jQuery(document).ready(function(){
	var itemArray = new Array("header_image1.jpg","header_image2.jpg","header_image3.jpg","header_image4.jpg","header_image5.jpg","header_image6.jpg","header_image7.jpg","header_image8.jpg");
	var rndNo = Math.floor(Math.random()*(itemArray.length));
	var itemHTML = "<img alt='Header image' src='/wp-content/themes/skysprout/images/" + itemArray[rndNo] + "' />";
	jQuery(".mainimageholder").empty();
	jQuery(".mainimageholder").append(itemHTML);
});