JSFiddle - React, Tailwind, and code Playground

HTML

<img src="http://placehold.it/350x300" class="mask">

CSS

.mask {
    width: 300px;
	height: 300px;
	border-radius: 150px;
	-webkit-border-radius: 150px;
	-moz-border-radius: 150px;
}