.img-bottom-half{
  min-height:500px;
  position: relative;
  display: block;
  width: 100%;
  height: 50vh;
  background-position: 50% 0%;
  background-size: cover;
  background-repeat: no-repeat;
}
@media screen and (max-width: 767px) {
  .img-bottom-half{
  min-height:300px;
}