JSFiddle - React, Tailwind, and code Playground

HTML

<div><img src="http://www.hawaiianimals.org/monkey-5263_whitw_op_640x480.jpg" alt=""></div>
<div><img src="http://ummahweb.net/wp-content/uploads/2010/04/z78.jpg" alt=""></div>
<div><img src="http://www.och.lt/uploads/posts/2012-05/1337279564_podb_6.jpg" alt=""></div>
<div><img src="http://xemanhdep.com/gallery/black_white_photos/black_white_photos26.jpg" alt=""></div>

CSS

div {
    border: 1px solid #CCC;
    width: 300px;
    height: 300px;
    margin: 10px;
    padding: 5px;
    position: relative;
}
img {
    max-height: 100%;
    max-width: 100%;
    display: block;
    margin: auto;
}