Bug 495431

SUMMARY
Koko have some caching issue, i explain, there is a folder i open quite often, so tumbnail are generated, yet every time i open it it take an insane amount of time (compared to dolphin to do the same) for loading all the thumbnail.

Also when we scroll this "loading" start again, making Koko very frustrating to use.

Once scrolled to the end the worse if we go back where thumbnail were already load ... they load again !!

I tried it both with full drive access permission set, and once with restricted permission to see if the flatpak could have forgotten to give permission to reach the "cache or thumbnail folder" it's not have changed anything.

STEPS TO REPRODUCE
1. Leave picture folder to another
2. increase thumbnail size (and wait all tumbnail to be created)
3. Close koko and restart it.
4. Go in the same folder and see.
5. Optionally scroll to see it worse.

OBSERVED RESULT
Long loading time of thumbnail like it was generating them one to one. scrolling make it load like the app never opened the folder before making it absolutly nightmarish to use.

EXPECTED RESULT
Load very fast after the inital thumbnail creation and continue to be loaded once scrolled up or down

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.2.2
KDE Plasma Version: 6.2.2
KDE Frameworks Version: 6.7.0 
Qt Version: 6.7.2

ADDITIONAL INFORMATION

Use Wayland and the Kernel 6.11.4 on Fedora 40