JSFiddle - React, Tailwind, and code Playground

HTML

<div class='triangle'>
    <img src="http://s.hswstatic.com/gif/landscape-photography-1.jpg"/>
</div>

CSS

.triangle{
    position: relative;
}
.triangle:before{
    border-top: 0;
    border-right: 200px solid white;
    border-bottom: 240px solid transparent;
    border-left: 160px solid white;
    position: absolute;
    content: "";
}