chromium/third_party/blink/web_tests/http/tests/priorities/resources/preload/as-image.html

<script src="../common.js"></script>
<script>
  observeAndReportResourceLoadPriority(new URL('../../../resources/square.png', location));
</script>

<link rel="preload" as="image" href="../../../resources/square.png" onload="reportLoaded()" onerror="reportFailure()"></script>