JSFiddle - React, Tailwind, and code Playground

HTML

<img src="http://audi-for-sale.com/wp-content/uploads/2010/04/audi-rs4.jpg" width="100" />
<img src="http://audi-for-sale.com/wp-content/uploads/2010/04/audi-rs4.jpg" width="100" height="100" />
<img src="http://audi-for-sale.com/wp-content/uploads/2010/04/audi-rs4.jpg" class="proportional" />
<img src="http://audi-for-sale.com/wp-content/uploads/2010/04/audi-rs4.jpg" class="non-proportional" />

CSS

.proportional {
    width: 100px;
}
.non-proportional {
    width: 100px;
    height: 100px;
}