I want to create a responsive two column element (25% and 75% width), with the height of the element being determined by an image within the left column. My code works, but the height is a few pixels larger than the image - why is that and how can I fix it?
.row {
  display: flex;
}
.s3 {
  flex: 25%;
}
.s9 {
  flex: 75%;
}
img {
  width: 100%;
}<div class="row">
  <div class="col s3" style="background-color: red;">
    <img src="https://picsum.photos/400/500">
  </div>
  <div class="col s9" style="background-color: green;"></div>
</div> 
    