<a href="javascript:void(0)" onMouseOut="hideImg()" onmouseover="showImg()">图片测试
</a> 
<div id="wxImg" style="display:none; position:absolute;"><img src="img/hello.jpg">
</div>

function showImg(){ 
                 document.getElementById("wxImg").style.display='block'; 
                } 
                  function hideImg(){ 
                  document.getElementById("wxImg").style.display='none'; 
                }