function openImage(sURL, nWidth, nHeight) {
	var winHeight = nHeight ? nHeight : 400;
    var winWidth = nWidth ? nWidth : 400;
    var winTop = (screen.height - winHeight) / 2;
    var winLeft = (screen.width - winWidth) / 2;

    var winObject = window.open(sURL, '', "height=" + winHeight + ", width=" + winWidth + ", top=" + winTop+", left=" + winLeft + ", status=no, toolbar=no, menubar=no, location=no, resizable=yes, scrollbars=no");
    if (winObject) {
        winObject.focus();
    }
}