Edit in JSFiddle

function setBgImgToEmptyUrlString() {
	$("#bgimg").css("background-image", "url('')");
$(document).ready(function() {
	setBgImgToEmptyUrlString();  // if u comment this out, then run again, u'll only c 1 request to "_display/"
<div id="bgimg">
css background-image url gets set by jquery in document.ready. an empty url string ("") will result in 2 requests instead of 1. when u run this n look at th "network" tab in chrome debugger, u'll c 2 requests to "_display/":
<img style="width:100%" src="http://i.imgur.com/AIFGCVt.png">


External resources loaded into this fiddle: