JSFiddle - React, Tailwind, and code Playground

HTML

<div class="bubble"></div>

CSS

.bubble {
    position:relative;
    height:200px;
    width:300px;
    background-image:url(http://th03.deviantart.net/fs31/200H/i/2008/225/e/7/Dahlia_13_by_andras120.jpg);
}
.bubble:before, .bubble:after {
    content:'';
    position:absolute;
    height:0;
    border-bottom:20px solid white;
    bottom:0;
}
.bubble:before {
    left:0;
    width:20px;
    border-right:16px solid transparent;
}
.bubble:after {
    left:36px;
    right:0;
    border-left:16px solid transparent;
}