No Covers

Good morning, sir,
Some covers are not displayed even though the file tag has an associated cover.
Do you have a solution?
Thank you in advance.

| have seen something like that when folder contained extremely large cover scan jpg file around 3000x3000 pixels.

No, all my covers are 600x600.

Currently I got the same problem with one folder, I tried to change jpg, re-scan nothing helped, then I found out that my other volumio on same network displayed this folder just fine (software version is latest on both). After that I removed all shares in source page, restarted and added shares again. After that problem was gone. I think this has nothing to do with folder content - it is some kind of persistent error in volumio database that goes away only by completely erasing and re-scanning.
At first I added share using different name and all was OK, but after I changed name back to original error returned. It seems Volumio cashes old database somewhere.
At last I pushed “remove all user data” at system page and after restart added share again, this time with original name - all is OK now. Must warn that this removes all installed plugins and resets all settings also.
NEW Edit:
Found correct and easy way to get rid of problem :
Sources -> Reset Album Art Cache after that Browse -> update folder.
Seems that sometimes cache gets corrupted.