JSFiddle - React, Tailwind, and code Playground

HTML

<div id="rectangle"><div id="triangle"></div></div>

CSS

#rectangle{width:300px; height:70px; position:relative; margin-top:100px; background:url(http://farm5.static.flickr.com/4004/4183276788_c6dec9c34f.jpg);}
#rectangle:before{position:absolute; content:""; width:100px; height:1px; background:gray; left:0; top:-25px;}
#rectangle:after{position:absolute; content:""; width:100px; height:1px; background:gray; left:200px; top:-25px;}
#triangle{width:100px; height:50px; background:url(http://farm5.static.flickr.com/4004/4183276788_c6dec9c34f.jpg) 100% 200%;  position:absolute; l;left:100px; top:-50px;}
#triangle:after{content:" "; position:absolute; width:0px; height:0px; top:0; left:0px;border:1px solid white; border-color:transparent white transparent white; border-width:0px 50px 50px 50px;}