My desktop is set to preview, but there are some small files, JPGs generated by screen shots,  which are generally (but now always) not previewed.  This is not much of a problem but it is irritating.  Any ideas on how to investigate?

The system:
Operating System: Fedora 34
KDE Plasma Version: 5.22.3
KDE Frameworks Version: 5.83.0
Qt Version: 5.15.2
Kernel Version: 5.13.4-200.fc34.x86_64 (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Core™ i7-4790K CPU @ 4.00GHz
Memory: 15.5 GiB of RAM
Graphics Processor: Mesa DRI Intel® HD Graphics 4600

-- 
Sincerely Jonathan Ryshpan <jonrysh@pacbell.net>

	If God lived on earth, people would break all 
	his windows.