var Stage = 1;
StartTimer();

function StartTimer()
{
    var Interval = 12000;
	window.setInterval ("UpdatePictures()", Interval);
}

function UpdatePictures()
{
    Stage += 1;
    if (Stage > 3) Stage = 1;
    document.getElementById ("PictureBox").filters[0].Apply();
    document.getElementById ("PictureBox").src = "Images/Pic" + Stage + ".jpg"
    document.getElementById ("PictureBox").filters[0].Play();
}