묻고답하기

<div style="position:absolute;" class="topMenuRightBtn">
                <ul class="pull-right">
                    <li>
                        <div class="">
<span id="dropDwonAlram" class="activity-dropdown" data-ui-type="dropdown-btn" data-dropdown-to="#alramContent"> 
<a href="javascript:badgeBtnClick();"><img src="img/dropDwon.png">

<div class="bot" style="padding-top:4px;">Notice</div></a>
<b class="badge bounceIn animated" id="topbadge" data-ui-type="badge" style="min-width:20px; display:none;"></b> 
</a>
 </span>
   </div>

 

대충 코딩은 이런데요 ...

화면을 줄였을때 이미지를 바꿔보이고 싶어요

어떻게해야되죠?