function changeImage(index) {
	var curImage = document.getElementById("imageDisplay");
	curImage.src=imgArray[index].src;
	curImage.alt=imgArray[index].alt;
	curImage.title=imgArray[index].alt;
	var caption = document.getElementById("caption");
	caption.firstChild.nodeValue = imgArray[index].alt;
	
}

function doPrev() {
	curIndex = (curIndex + (imgCount-1)) % imgCount;
	changeImage(curIndex);

}
function doNext() {
	curIndex = (curIndex + 1) % imgCount;
	changeImage(curIndex);
}