<div class="box">
  <div class="img-container">
    <img src="https://cdn-images-1.medium.com/max/1600/0*tuDPftoIhupd-qx-.jpg" alt="">
  </div>
</div>

<div class="box">
  <div class="img-container">
    <img src="https://cdn-images-1.medium.com/max/1600/0*tuDPftoIhupd-qx-.jpg" alt="">
  </div>
</div>

<div class="box-vw">
  <div class="img-container">
    <img src="https://cdn-images-1.medium.com/max/1600/0*tuDPftoIhupd-qx-.jpg" alt="">
  </div>
</div>

* {
  margin: 0;
  padding: 0; 
}

body {
  padding: 15px;
}

.box,
.box-vw {
  background-color: #010102;
  border-radius: 10px;
  overflow: hidden;
  margin-bottom: 15px;
}

.box:nth-of-type(2) {
  width: 260px;
}
/* vw */
.box-vw .img-container {
  width: 100vw;
  height: 66.620879vw;
  padding-bottom: inherit;
}
/* padding */
.img-container {
  width: 100%;
  height: 0;
  /* Aspect ratio of picture*/
  padding-bottom: 66.620879%;
}

img {
  width: 100%;
}