JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li><img src="http://kinogo.net/uploads/posts/2015-04/thumbs/1429207318_nochnoybeglez.jpg" alt=""></li>
    <li><img src="http://kinogo.net/uploads/posts/2015-04/thumbs/1429207318_nochnoybeglez.jpg" alt=""></li>
    <li><img src="http://kinogo.net/uploads/posts/2015-04/thumbs/1429207318_nochnoybeglez.jpg" alt=""></li>
    <li><img src="http://kinogo.net/uploads/posts/2015-04/thumbs/1429207318_nochnoybeglez.jpg" alt=""></li>
</ul>

CSS

ul {
    width: 250px;
    margin: 20px auto;
    list-style-type: none;
}
li { margin: 10px 0;}

JavaScript

$(document).ready(function(){
    $('li').hover(
      function() {
        $(this).find('img').stop().fadeTo(500,0.1);
      },
      function() {
        $(this).find('img').stop().fadeTo(500, 1);
      }
    )
});