Edit in JSFiddle

<div class="box">
  <img class="top-img" src="https://demo.cssworld.cn/images/6/top1.png" />
  <img class="bg-img" src="https://demo.cssworld.cn/images/common/l/1.jpg" />
</div>
.bg-img {
  width: 100px;
}
.top-img {
  position: absolute;
  width: 40px;
}
.box {
  width: 100px;
  display: inline-block;
      }