var counter = 0;
var numImgs = imgArr.length;

function nextImg() {
	if ((counter+1) == numImgs) {
		counter = -1; 
	}
	counter++;
	document.smallImg.src=imgArr[counter];
	var href = "javascript:viewImage('" + largeimgArr[counter] + "')";
	document.anchors[0].href=href;
}

function prevImg() {
	if (counter == 0) {
		counter = numImgs;
	}
	counter--;
	document.smallImg.src=imgArr[counter];
	var href = "javascript:viewImage('" + largeimgArr[counter] + "')";
	document.anchors[0].href=href;
}

function viewImage(img) {
	var url = "viewimage.php?img=" + img;
	var win = window.open(url,'ImageView','width=600,height=500');
}