Делаем автоматическую смену фона сайта без перезагрузки

<img  src="" alt="background" id="bg" style="display:none" />
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script> 
<script type="text/javascript" class="noprint">
	var aImages = new Array();
	var aURL = new Array();
	var aArtists = new Array();
	var iPrev = -1;
	var iRnd = -1;
 
	aImages[0] = "templates/_default_/images/bg/bg.jpg";
	aImages[1] = "templates/_default_/images/bg/bg1.jpg";
	aImages[2] = "templates/_default_/images/bg/bg2.jpg";
	aImages[3] = "templates/_default_/images/bg/bg3.jpg";
 
 
 
 
	$(document).ready(function() {
 
 
		$("img#bg").load(function()
			{
 
				$("img#bg").fadeTo(2000,1);
 
 
 
		    	setTimeout(function() 
			    	{
			    		$("#image_description").animate({right: '-=150'}, 1000);
			    		$("img#bg").fadeOut(2000);
 
 
			    		setTimeout(LoadImages,2500);
			    	}
			    	,30000);
			}			
		)
 
 
		setTimeout(LoadImages,1000);
 
    });
 
    function LoadImage(iNr)
	{
 
		$("img#bg").attr("src", aImages[iNr]);
 
 
    };
 
    function LoadImages()
    {
 
    	/* Select a random image number and make sure this is not equal to the previous image */
    	while(iPrev == iRnd)
    	{
    		iRnd = Math.floor(Math.random()*aImages.length);
    	}
 
    	/* Show the selected image */
    	LoadImage(iRnd);
 
    	iPrev = iRnd;
 
    };
</script> 

img#bg {
    /* Stretch background */
        position: fixed;
    top:0;
    left:0;
    width:100%;
    z-index:-3;
}