Thumbnail for video doesn't load

Assigned an item for thumbnail, but it doesn't load. I went poking through the module code and am unsure if this is a bug. In the videojs.theme.inc file:

  foreach ($items as $item) {
    if (!isset($codecs[$item['filemime']])) {
      // check for image file and add in it as poster
      $image = file_validate_is_image((object) $item);
      if (empty($image)) {
        $vars['poster'] = file_create_url($item['uri']);
      }

      // Skip unplayable items.
      continue;
    }

    $item['videotype'] = $codecs[$item['filemime']];

    $vars['items'][] = $item;
  }

It seems like it's checking for a poster image (it was finding mine), but then ignoring the results.

I was able to get it working on my end by changing line 36 to:

if (!empty($image)) {

I am still fairly new to Drupal and haven't reviewed the whole module's code in detail, so I apologize in advance if I'm maybe just not using it correctly.