$('a[rel=lightbox]').lightBox({
	overlayBgColor: '#000',
	overlayOpacity: 0.8,
	containerResizeSpeed: 500,
	txtImage: 'Zdjęcie',
	txtOf: 'z'
   }).each(function(){
    $(this).addClass('lightbox').append("<img src='img/preview.gif' class='preview' />");
   });