</body>
</center>
<p><a href="MY WEBSITE LINK" target="_blank"><img src="IMAGE LINK" border="0" alt="Null"></a></p>
</center>
</body>

<p>
  <a href="MY WEBSITE LINK" target="_blank">
    <img src="IMAGE LINK" style='width:100%;' border="0" alt="Null">
  </a>
</p>

<img src="IMAGE LINK" border="0" class="responsive-image" alt="Null">

.responsive-image{
        height:auto;
        width:100%;
    }

max-width: 100%;
display:block;
height: auto;