<style>
.alignwiththis {
  display:inline-block;
  height: 200px;
  width: 200px;
  background-color: blue;
}
.overflownotvisible {
  display: inline-block;
  height: 200px;
  width: 200px;
  background-color: green;
  overflow: hidden;
}
</style>
PASS if the boxes below are aligned ("overflow: hidden" -> baseline is the bottom of the margin box).
<div>
  <div class=alignwiththis></div>
  <div class=overflownotvisible>
    <div><img src="foo" style="width: 0px; height: 0px;"></div>
  </div>
</div>