chromium/third_party/blink/web_tests/http/tests/images/jpeg-partial-load.html

<img style="background: green" >
<script>
if (window.testRunner) {
    testRunner.dumpAsTextWithPixelResults();
    testRunner.waitUntilDone();
}

function loadAndStall()
{
    return "http://127.0.0.1:8000/resources/load-and-stall.php";
}

function jpegImage()
{
    return "?name=../../../images/resources/gracehopper.jpg&mimeType=image%2Fjpeg";
}

function testDone()
{
    window.testRunner && testRunner.notifyDone();
}

function runTest()
{
    document.querySelector("img").src = loadAndStall() + jpegImage() + "&stallAt=26337&stallFor=60";
    setTimeout(testDone, 1500);
}

window.onload = function() {
    setTimeout(runTest, 0);
}
</script>