the wallpaper chooser does not show some (most) thumbnails, but clicking on one of the "broken" thumbnails the wallpaper is properly installed nonetheless. I've attached a screenshot showing the issue. Reproducible: Always
Created attachment 97370 [details] screenshot showing the issue
(In reply to Fabio Coatti from comment #0) > the wallpaper chooser does not show some (most) thumbnails, but clicking on > one of the "broken" thumbnails the wallpaper is properly installed > nonetheless. > I've attached a screenshot showing the issue. > > > > Reproducible: Always Is the Dolphin showing the thumbnails ? What is the format of the missing thumbnails ? Do you have a thumbnailer for the missing thumbnails ? Can you upload an example file which the wallpaper chooser can't show the thumbnail ? Same kind of - [SOLVED] No wallpaper preview on desktop settings in KDE : https://bbs.archlinux.org/viewtopic.php?id=206500 The problem was missing thumbnailer.
Thanks for the help, you pointed me in the right direction. Dolphin was, in fact, not able to draw jpeg thumbnails and all missing wallpapers thumbnails were jpg. However, all files and dynamic libs were installed on my system. Out of ideas I reinstalled kio-extras (that basically means recompilation, on gentoo) and this fixed the issue. Many thanks for the help!
Ok, closing this bug then, as it seems to have been an installation problem.