JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <div class="image-container">
        <img src="https://via.placeholder.com/500" alt="image">
    </div>
</body>

CSS

.image-container {
   height: 100px;
   width: 100px;
   border: 5px solid red;

   /* 
      without this the image will use it's original size, 
      it'll go outside of the flow of elements
      and no longer respect the width: 100% set on img below
      it'll be relative to the root of the page (html)
   */
   position: relative; /* remove this to check */
 }

 .image-container img {
   position: absolute;
   width: 100%;
 }