JSFiddle - React, Tailwind, and code Playground

HTML

<div class="post">
  <img src="https://dummyimage.com/1920x1080/000/fff" width="1920" height="1080" data-ratio-id="1"/>
</div>

CSS

.post { /* just an example of stles with max-width */
  max-width: 320px;
  border: 1px solid red;
  line-height: 0;
}
/* Some magic with ::before */
img[data-ratio-id] {
  max-width: 100%;
  height: auto;
  display: inline-block;
}
img[data-ratio-id]::before { 
  content: '';
  display: inline-block;
}
img[data-ratio-id="1"]::before {
  padding-top: 56.25%;
}