If you hover over the `<a>` surrounding the image on the test page, you'll see that the highlighted box is too high and doesn't match the highlight you get in the Elements panel. This code seems to work better:

``` js
  var bounds = element.getBoundingClientRect();
  hoverElement.style.left = bounds.left + 'px';
  hoverElement.style.top = bounds.top + 'px';
  hoverElement.style.width = bounds.width + 'px';
  hoverElement.style.height = bounds.height + 'px';
```