chromium/third_party/blink/web_tests/external/wpt/css/css-viewport/zoom/background-image.html

<!doctype html>
<title>Zoom affects background-image intrinsic sizes</title>
<link rel="help" href="https://drafts.csswg.org/css-viewport/#zoom-property">
<link rel="match" href="background-image-ref.html">
<style>
div {
  width: 20px;
  height: 20px;
  zoom: 0.5;
  background-image: url("/images/pattern.png"); /* 20x20 */
}
</style>
<div></div>