How can I pull media:thumbnail from an RSS feed with SimplePie and fetch_feed()?
There is another way to solve this. I had a similar problem. I realized I had not used media:thumbnail but only media:content. In order to get the link I used the following code:
echo '<img src="' . $enclosure->get_link() . '" class="feed-thumb" />';
Instead of calling for the thumbnail, I called for the link and the situation was solved.