function UpdateXBlock(image)
{
    var img = $('#xblock > img');
    var img2 = img.clone();
    img2.attr('src', 'images/' + image);
    img2.css({
        opacity: 0
    });
    img2.insertAfter(img);

    img.animate({
        opacity: 0
    }, function(){
        $(this).remove();
    });
    img2.animate({
        opacity: 1
    });
}