JSFiddle - React, Tailwind, and code Playground

HTML

<img id="myimg" src="https://images.freeimages.com/images/small-previews/867/volcanic-mt-ngauruhoe-1378772.jpg" onmouseover="mouseover()" onmouseout="mouseout()" />

JavaScript

function mouseover() {
  const elm = event.target;
  elm.setAttribute("orig_src", elm.src);
  elm.src = "https://images.freeimages.com/images/small-previews/647/snowy-mountain-1378865.jpg";
}

function mouseout() {
  const elm = event.target;
  elm.src = elm.getAttribute("orig_src");
}