It seems that Newsblur doesn’t understand that the feed provides the same image in multiple resolutions.
Actually what NewsBlur is doing is showing all of the enclosures. The feed is saying it has all of these images available. I could probably be smarter about how I manage enclosures which try to declare the same thing.
So I checked and it seems the feed isn’t even trying to differentiate between images. So they are effectively saying that all of those images are enclosures and they should be offered to the user.