<div id="slideInner">
        <div class="slide" id="slide1">
         <img src="img/fon1.jpg">
        </div>
        <div class="slide" id="slide2">
          <img src="img/fon2.jpg">
        </div>
        <div class="slide" id="slide3">
          <img src="img/fon3.jpg">
        </div>
      </div>

$("#slideInner").eq(0).clone().appendTo("#slideInner");
$("#slideInner").eq(0).remove()

$('#slideInner > div:first').remove().appendTo('#slideInner');

$("#slideInner").append( $("#slide1") );