JSFiddle - React, Tailwind, and code Playground

HTML

<li class="article">
    <div class="img">
        <a href="#">
            <img src="http://i.telegraph.co.uk/multimedia/archive/02371/karen-ann-jones_2371086k.jpg" alt="Url">
        </a>
    </div>
</li>

CSS

.article img {
  margin-bottom: 5px;
  -moz-border-radius: 15px;  /* for Firefox */
  -webkit-border-radius: 15px; /* for Webkit-Browsers */
  border-radius: 15px; /* regular */
}

.article:hover .img {
  opacity: 0.8;
}