JSFiddle - React, Tailwind, and code Playground

HTML

<div class="thumb" style="background-image: url('http://24.media.tumblr.com/tumblr_ly7xjxn3QI1r62v9yo1_1280.png');" title="Portrait: 400x800"></div>

<div class="thumb" style="background-image: url('http://fc02.deviantart.net/fs70/f/2011/125/a/4/retold_with_unicorns_by_biotwist-d3fn77s.jpg');" title="Landscape: 800x400"></div>

CSS

.thumb {
    display: inline-block;
    width: 200px;
    height: 200px;
    margin: 5px;
    border: 3px solid #c99;
    background-position: center center;
    background-size: cover;
}