function preload() {
	
		var buffer = new Array();
		var b=0;
		var tail;
		var jup;

		var images = document.images;		
		
		for (var i=0; i < images.length; i++) {
		
			if (images[i].name != null && images[i].name.match(/but$/)) {
			
				buffer[b] = new Image();
				buffer[b].src = images[i].src.replace(/1\.gif$/,"2.gif");
				images[i].src1 = images[i].src;
				images[i].src2 = buffer[b].src;				
				b++;

			}
		}
	}

	preload();
	
	
	function onRollOver(button) {

		button.src = button.src2;

	}
	
	function onRollOut(button) {

		button.src = button.src1;
	}