//store an interval in a variable
var pause = 3000;
//create counter
var n = 0;
//create array
var imgs = new Array ( "happytrader.jpg", "happytrader2.jpg", "happytrader3.jpg", "happytrader4.jpg" );

//preload all the images
var preload = new Array();
for( var i = 1; i < imgs.length; i++ )
{
	preload[i] = new Image();
	preload[i].src = imgs[i];
	}
	
//display each image
function rotate()
{
	document.images.pic.src = imgs[n];
	( n == (imgs.length - 1 )) ? n = 0 : n++;
	setTimeout( "rotate()", pause );
	}

//specify onload event-handler
window.onload = rotate;