JSFiddle - React, Tailwind, and code Playground

HTML

<div class="hover"><div></div></div>

CSS

.hover {
    height: 100px;
    width: 346px;
    border: 1px solid #ccc;
    background: url(http://dl.dropbox.com/u/2794221/logo.jpg) center top;
}
.hover div {
    background: url(http://dl.dropbox.com/u/2794221/logo.jpg) center bottom;
    height: 100%;
    width: 100%;
    display: block;
    -webkit-transition: opacity .7s;
    -moz-transition: opacity .7s;
    -o-transition: opacity .7s;
    transition: opacity .7s;
}

.hover:hover div {
    opacity: 0;
}