transparent-gif-paint-background.html

<!doctype HTML>
<!doctype HTML>
<style>
img {
  display: block;
  background-color: blue;
}
</style>
Test passes if green is seen.
<!-- This is a 100x100 fully transparent gif -->
<img id="image" src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" width="100" height="100"/>
<script>
  if (window.testRunner)
    window.testRunner.waitUntilDone();
  onload = () => {
    requestAnimationFrame(() => {
      requestAnimationFrame(() => {
        const image = document.getElementById("image");
        image.style.backgroundColor = 'green';
        if (window.testRunner)
          window.testRunner.notifyDone();
      });
    });
  };
</script>

chromium/third_party/blink/web_tests/images/transparent-gif-paint-background.html