function highlightImg(imgKey, imgValue, titleKey, titleValue) {
        if (document.images) {
            document[imgKey].src = imgValue;
            document[titleKey].src = titleValue;
        }
}

function swapImg(img_1, img_2) {
        if (document.images) {
			tmp = document[img_1].src;
			document[img_1].src = document[img_2].src;
			document[img_2].src = tmp;
        }
}