var lastID = "1";

function selectImg(id, caption) {
	if (lastID > 0)
		document.getElementById(lastID).className = "thumbNormal";
	document.getElementById(id).className = "thumbSelected";
	regex = "_tth";
	var src = document.getElementById(id).src;
	src = src.replace(regex, '');
	document.getElementById("0").src = src;
	
	document.getElementById("0").alt = caption;
	document.getElementById("0").title = caption;
	
	lastID = id;
}