Why some public Feature Photos don't display when Logged Out

WinsomeWorks

I've been trying to get all through my website while logged out, just to take a look at everything since the transition. I keep finding folders (especially subfolders) & also galleries, which are not displaying their featured photo. These are featured photos that display fine when I'm logged in. And they're from listed galleries, not unlisted ones, just as they were in my legacy SmugMug. Not marked "hidden", either.

I haven't been able to figure out why some of them don't show when I'm logged out. I've so far been successful in getting either the same one to show, or if not, a different one in the same gallery, by resetting it 1, 2, or 3 times. But I'd like to know what's going on. Can anyone think of reasons why certain feature photos wouldn't appear to the public? I'm out of ideas. P.S... None of these were an issue in my legacy site. What I see instead of the feature photo is just a blue tile with the folder or sub-folder or gallery name, & no "Unlisted" sign.

leftquark

It would help if you could post links to the Folders in which they don't show up / include some screenshots (though the links are far more useful). New SmugMug has been extensively used for 2 years and we aren't seeing any issues with Feature Images, unless there's a new problem.