var photoUpdateTimer = -1;
var photoNo = 1;
var maxPhotos = 23;

function initPhotoUpdateTimer() {
	for(var i = 1; i < maxPhotos; i++) {
		var dmy = newImage("images/main/" + i + ".jpg");
	}
	photoUpdateTimer = setTimeout("changePhoto()", 25000);
}

function changePhoto() {
	photoUpdateTimer = -1;
	photoNo++;
	if(photoNo > maxPhotos)
		photoNo = 1;

	var img = document.getElementById('mainPhoto');
	img.src = "images/main/" + photoNo + ".jpg";
	photoUpdateTimer = setTimeout("changePhoto()", 4000);
}