JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://imgur.com/a/k1P2o"></script>
<script src="https://imgur.com/a/aMFuB"></script>
<body class="asyncImage" data-src="https://i.imgur.com/EWx6Ao5.jpg">
  <div class="container">
    <p>
      Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
    </p>
  </div>
</body>

CSS

body {
  background-image: url('https://i.imgur.com/ffmMq6q.jpg');
  background-repeat: no-repeat;
  background-size: cover;
}

.container {
  width: 700px;
  margin: 0 auto;
}

JavaScript

(() => {
  'use strict';
  // Page is loaded
  const objects = document.getElementsByClassName('asyncImage');
  Array.from(objects).map((item) => {
    // Start loading image
    const img = new Image();
    img.src = item.dataset.src;
    // Once image is loaded replace the src of the HTML element
    img.onload = () => {
      item.classList.remove('asyncImage');
      return item.nodeName === 'IMG' ? 
        item.src = item.dataset.src :        
        item.style.backgroundImage = `url(${item.dataset.src})`;
    };
  });
})();