function tSwap(swapNum){

document.thumb_swap.src="swap_0" + swapNum + ".jpg";
		
	for(var i=1;i<14;i++){
	if (i==swapNum)
	document.getElementById("swap" + i ).style.visibility="visible";
	else
	document.getElementById("swap" + i).style.visibility="hidden";
	}

}