The Feedzy feeds began working better after I redid some of the links.
Some of my feeds, however, still do not consistently pull in the thumbnail images from articles that have images. I have replaced the default Feedzy logo (which is supposed to take the place of the article’s thumbnail where there is no image) with my site’s logo. I do see my logo appearing on some articles in some feeds.
So this is fixed, but not with 100% consistency. See this link for an example:
https://bit.ly/2TqpQh1
Also note that where an image has transparency (a GIF or PNG) I can see part of my default logo underneath the article’s image.
The article’s image should replace the default logo, not simply display on top of it.