chromium/chrome/test/data/load_image/image.html

<html>
<head></head>
<img alt="long_placeholder_text" src="image.png" />
<script src="common.js"></script>
<script>
function loadNewImage(url) {
  return new Promise((resolve, reject) => {
    document.images[0].onload = () => {
      console.log('new image loaded', url);
      resolve(true);
    };
    document.images[0].src = url;
  });
}
</script>
</html>