chromium/src/third_party/blink/web_tests/http/tests/priorities/resources/service-worker/off-screen-image.html

<script src="../common.js"></script>
<script>
  const image = new Image();
  image.src = '../../../resources/square.png?getPriority';

  image.onload = reportLoaded;
  image.onerror = reportFailure;
</script>