var bannerPhotosQuantity = 4

bogurskiBanner = function() {
    image_no = Math.round(Math.random() * bannerPhotosQuantity + 1);
    jQuery('#banner_img').animate({opacity: 'toggle'}, 1500, function() {
        jQuery('#banner_img').attr("src", '/bogurski_banner/' + image_no + '.jpg');
        jQuery('#banner_img').animate({opacity: 'toggle'}, 1500, function(){
            setTimeout("bogurskiBanner()",7000);
        })
    });
}
jQuery(function() {
    image_no = Math.round(Math.random() * bannerPhotosQuantity + 1);
    jQuery('#banner_img').attr("src", '/bogurski_banner/' + image_no + '.jpg');
    setTimeout("bogurskiBanner()", 7000);
});