Bug 404657

It seems to be the same issue as https://bugs.kde.org/show_bug.cgi?id=331240

but this was strangely marked as solved while this is clearly NOT SOLVED AT ALL. All people I asked to reproduce it CAN REPRODUCE IT ON NEWEST versions of packages.

STEPS TO REPRODUCE
1. Create a folder with all photos above 3MB.
2. Go up in the folder structure and you will see just general folder icon, but no preview icons of the photos inside.
3. Downsize one photo to the size below 3MB, you will see its image on the folder preview. Have at least 4 of such photos, you will get 4 images to preview icons on a folder icon.

The issue is: 3MB cap is arbitrary set and there is no Dolphin setting to change that. We can for example set image size of network images preview but not this one? It seems strange. The default 3MB cap may be OK as a default but still should be changeable since many of the photos taken by smartphones are above 3MB. It feels like this was set many years ago but no one cared to update it to the current standards. So either we get a higher cap (at least 6MB) or let us have this as an option which would be preferable because any arbitrary, static cap won't be good for some person or use case.


SOFTWARE/OS VERSIONS
Operating System: Manjaro Linux 
KDE Plasma Version: 5.15.1
KDE Frameworks Version: 5.55.0
Qt Version: 5.12.1
Kernel Version: 4.20.10-1-MANJARO
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-6700HQ CPU @ 2.60GHz
Memory: 7,7 GiB