JSFiddle - React, Tailwind, and code Playground

HTML

<div id="contain" class="thumb"></div>
<div id="cover" class="thumb"></div>

CSS

.thumb {
    background-color: #CCC;
    background-image: url('http://www.google.com/images/logos/ps_logo2.png');
    background-position: center center;
    background-repeat: no-repeat;
    border: 1px solid #000;
    margin: 5px;
    width: 100px;
    height: 100px;
}

#contain {
    background-size: contain;
    -moz-background-size: contain;
}
#cover {
    background-size: cover;
    -moz-background-size: cover;
}