JSFiddle - React, Tailwind, and code Playground

HTML

<div id="over">
    <img src="http://cdn.sstatic.net/stackoverflow/img/apple-touch-icon.png" />
</div>

<h4>In this case the outer box is not 200x200px</h4>

CSS

#over {
    width: 200px;
    line-height: 200px;
    border: 1px solid #bbb;
}
#over img {
    display: block;
    margin-left: auto;
    margin-right: auto;
    border: 1px solid #bbb;
}