#znak a {
    width: 131px;
    height: 347px;
    display: block;
    background: url(../images/znak.png) 0 top no-repeat;
}

#znak a.active {
    background: url(../images/znak.png) -129px top no-repeat;
}

<div id="znak">
                        <a href="#"></a>
                    </div>

$('#znak a').hover(function() {
    $(this).animate({opacity: '0'}, {duration: 100, complete: function(){$(this).addClass('active');}})
.animate({opacity: '1'}, 100);},
    function() {
    $(this).animate({opacity: '0'}, {duration: 100, complete: function(){$(this).removeClass('active');}})
.animate({opacity: '1'}, 100);});