var swapSpeed = 1000;
var Background = new Array('template/bg.jpg','template/bg2.jpg','template/bg3.jpg','template/bg4.jpg'); 
var jss = 0;
var pss = Background.length-1;

var preLoad = new Array();
for (iss = 0; iss < pss+1; iss++){
	preLoad[iss] = new Image();
	preLoad[iss].src = Background[iss];
}


function backSwap() {	
	if(document.getElementById('swappingImage')) {
		document.getElementById('swappingImage').src = preLoad[jss].src;
		jss = jss + 1;
		if (jss > (pss)) jss=0;
		setTimeout('backSwap()', swapSpeed);
	}
}

backSwap();