function switch_img(divName, totalImgs) {
	for (var i=1; i<=totalImgs; i++  ) 
	{
		var showDivName = 'photo_'  + i;
		var showObj = document.getElementById(showDivName);
		if (showDivName == divName)
			showObj.style.display = 'block';
		else
			showObj.style.display = 'none';
	}
}