var visibleImage = "";//stores the ID of any visible image
function showThumb(imgIndex){

	hideThumb();//call func to hide any showing thumbnails

	var objImage = document.getElementById(imgIndex);
	objImage.style.visibility = 'visible';
	visibleImage = imgIndex
	var objHideTransparent = document.getElementById("transparent").style;
	objHideTransparent.visibility = 'visible';

}

function hideThumb(){

	if (visibleImage != ""){
		var objHideImage = document.getElementById(visibleImage).style;
		objHideImage.visibility = 'hidden';
		visibleImage= ""
		var objHideTransparent = document.getElementById("transparent").style;
		objHideTransparent.visibility = 'hidden';
	}
}