JSFiddle - React, Tailwind, and code Playground

HTML

<div class="full-width top-picture">
    <img src="http://backgroundland.com/wp-content/uploads/2014/07/Wonderful-Purple-Bridge-Wallpaper.jpg" />
</div>
<div class="full-width bottom-picture">
    <img src="http://backgroundland.com/wp-content/uploads/2014/07/Wonderful-Purple-Bridge-Wallpaper.jpg" />
</div>

CSS

.full-width img {
    width: 100%;
    height: auto;
}
.top-picture {
    height: 350px;
    overflow: hidden;
}
.bottom-picture {
    position: relative;
    top: -200px;
    overflow: hidden;
    border-top: 2px solid white;
    -webkit-border-top-left-radius: 50%;
    -webkit-border-top-right-radius: 50%;
    -moz-border-radius-topleft: 50%;
    -moz-border-radius-topright: 50%;
    border-top-left-radius: 50%;
    border-top-right-radius: 50%;
}