JSFiddle - React, Tailwind, and code Playground

HTML

<div id="background">
<img id="image" src="https://upload.wikimedia.org/wikipedia/commons/c/c3/Aurora_as_seen_by_IMAGE.PNG">
</div>

CSS

#background {
  background: blue;
  padding: 5px;
}

.p{
  width: 50px;
  height: 50px;
  background: red;
}

JavaScript

var obrazek = document.getElementById('image'); 
var width = obrazek.width;
var height = obrazek.height;


var platno = document.getElementById('background');
platno.style.width = width+"px";
platno.style.height = height+"px";