body {
margin: 0;
background: red;
}
div#back {
position: relative;
height: 200px;
background-image: url(http://wearepeak.co.uk/wp-content/uploads/2016/02/testimonial.jpg);
width: 100%;
border-bottom-left-radius: 70% 60px;
border-bottom-right-radius: 30% 10px;
}