TileMill Icons in Legend

gistfile1.css

<div class='my-legend'>
<div class='title'>Activity Type<br></div>
<div class='scale'>
  <ul class='labels'>
    <li><img src="https://s3.amazonaws.com/pdb.www/hiking-3.png"  />Hiking</li>
    <li><img src="https://s3.amazonaws.com/pdb.www/mountainbiking-3.png" />Biking</li>
  </ul>
</div>
</div>

<style type='text/css'>
  .wax-legends {  
        bottom:90px!important;
        right: 60px !important;
        height:100px!important; 
        width:90px!important;
    }
  .wax-legend .title {
    text-align: left;
    margin-bottom: 8px;
    font-weight: bold;
    font-size: 90%;
    }
  .wax-legend .scale ul {
    margin: 0;
    padding: 0;
    float: left;
    list-style: none;
    }
  .wax-legend .scale ul li {
    display: block;
    float: left;
    width: 50px;
    margin-bottom: 6px;
    text-align: center;
    font-size: 80%;
    list-style: none;
    }
  .wax-attribution a,
  .wax-legend a {
    color: #777;
    }
</style>