Jpg thumbnail issue on Mojave

Ok, i've got solution!

1. Turn off your Mac
2. Trun on and hold SHIFT whole time until u see login screen
3. Log in and check finder, if everthing is OK
4. It itś OK, restart your Mac normally and it should be ok.

Finder, Menu > View > Show View Options (Command - J),

& check the box: Show icon preview:

Same issue here, "show icon preview" checked and still doesnt work :/

Doesn't work!!! Any ideas?

This did not fix the problem.

didn't work. sometimes when I click on the thumbnail with Quick Look and I close it, the photo shows but not always and I can't do that with 1000's of photos