input-image-button-with-empty-value.html

<!DOCTYPE html>
<p>crbug.com/625604: Don't display fallback content when value attribute is empty rather than null. </p>
<input value="" type="image" style="background-image: url('data:image/gif;base64,R0lGODdhAgACAIABAAAAAP///ywAAAAAAgACAAACA0QCBQA7'); display: block;">
<input value="" type="image" style="display: block;">

chromium/third_party/blink/web_tests/fast/forms/input-image-button-with-empty-value.html