[jQuery] A Simple Question ! (mouseover)

<span></span>
<img src="1.jpg"></img>
<span></span>
<img src="2.jpg"></img>
<span></span>
<img src="3.jpg"></img>

$(document).ready(function() {

   $("img").mouseover(function(){
                  $("span").html("<img src="hover.jpg">");
});

  $("span").mouseout(function(){
           $(this).html("");
});

});

Mouse point to IMG1, all of it hover,
How can I piont to IMG1, IMG1 hover, and IMG2 , IMG2 hover only .