JSFiddle - React, Tailwind, and code Playground

HTML

<div id="cf">
  <img class="bottom" src="http://addnectar.co.in/ovenfresh/ovenfresh/admin/files/products/Sunny-29-07-2014-img-06-07-40.jpg" />
  <img class="top" src="http://addnectar.co.in/ovenfresh/ovenfresh/admin/files/products/Sunny-29-07-2014-img-07-45-01.jpg" />
</div>

CSS

#cf {
  position:relative;
  height:281px;
  width:450px;
  margin:0 auto;
}

#cf img {
  position:absolute;
  left:0;
  -webkit-transition: opacity 1s ease-in-out;
  -moz-transition: opacity 1s ease-in-out;
  -o-transition: opacity 1s ease-in-out;
  transition: opacity 1s ease-in-out;
}

#cf img.top:hover {
  opacity:0;
}