chromium/chrome/browser/page_load_metrics/integration_tests/data/is_animated.html

<img src="/images/anim-gr.png">
<script>
const run_test = async () => {
  await new Promise(resolve => {
    new PerformanceObserver(list => resolve())
      .observe({type: "largest-contentful-paint", buffered: true});
  });
};
</script>