JSFiddle - React, Tailwind, and code Playground

HTML

<div id="section0">

</div>

CSS

#section0{
     opacity: 0;
     transition: opacity 2s; /* Define the duration of the opacity animation */
     background-image: url("https://media.giphy.com/media/tIeCLkB8geYtW/giphy.gif");
     height: 500px;
     width: 500px;
}

JavaScript

setTimeout(function(){ 
  $("#section0").css({
       "opacity" : 1,
       "background-image": "url(https://media.giphy.com/media/tIeCLkB8geYtW/giphy.gif)"
  });
}, 300);