var picGroup = 1;
var maxGroup = 2;

function thumb(i) {
	return i.substring(0, (i.length-4)) + '_tn.jpg';
}

function moveLeft() {
	if (picGroup - 1 >= 1) {
		document.getElementById('pics'+picGroup).style.display = 'none';
		document.getElementById('pics'+(picGroup-1)).style.display = 'block';
		picGroup--;
	}
}

function moveRight() {
	if (picGroup < maxGroup) {
		document.getElementById('pics'+picGroup).style.display = 'none';
		document.getElementById('pics'+(picGroup+1)).style.display = 'block';
		picGroup++;
	}
}