Created attachment 138005 [details]
screenshot of some icons in the desktop

SUMMARY

When I save or copy some image files to the Desktop, the thumbnails that are displayed have very poor quality.

I attach a screenshot. All the actual images in the screenshot are about 4-5 times the size of the thumbnail, so the thumbnails are scaled down.

I can scale down the images to the same size as the thumbnails in GIMP and they don't look nearly as bad, so there's no reason why the quality should be so poor.

They look much better when you browser a folder in Dolphin instead of looking at the desktop.

I'm assuming the desktop is rendered by Dolphin, apologies if that's not the case.


STEPS TO REPRODUCE
1. Download some high-quality jpeg image of more than 550x350 pixels in size
2. save or copy it to the desktop
3. look at the desktop

OBSERVED RESULT

The quality of the thumbnail is very bad

EXPECTED RESULT

The quality of the thumbnail should be as high as reasonably possible without impacting performance.


Operating System: openSUSE Tumbleweed 20210414
KDE Plasma Version: 5.21.4
KDE Frameworks Version: 5.81.0
Qt Version: 5.15.2
Kernel Version: 5.11.12-1-default
OS Type: 64-bit
Graphics Platform: X11
Processors: 8 × Intel® Core™ i7-1065G7 CPU @ 1.30GHz
Memory: 7.3 GiB of RAM
Graphics Processor: Mesa DRI Intel® Iris® Plus Graphics