image-orientation-mask-image-ref.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Reference</title>
<style>
div {
  width: 100px;
  height: 50px;
  background: blue;
  mask-mode: luminance;
}
.orient { mask-image: url(../support/exif-orientation-2-ur-pre-rotated.jpg); }
.no-orient { mask-image: url(../support/exif-orientation-9-u.jpg); }
</style>
<div class="orient"></div>
<div class="no-orient"></div>

chromium/third_party/blink/web_tests/external/wpt/css/css-images/image-orientation/reference/image-orientation-mask-image-ref.html