Since upgrading to Kubuntu 26.04 LTS, images are no longer displayed

[Schwarzer Kater]

Hm…
Did you prophylactically erase your user account's caches after release-upgrading to Kubuntu 26.04?

Could help, but will do no harm if it doesn't (at least I have never had any problems in KDE Plasma doing that - I have had little inconveniences after erasing user caches with Linux Mint though, it had something to do with Cinnemon and 3rd party add-ons).

-> Restart your computer -> don't log in -> on the log in screeen press [Ctrl] [Alt] [F5] -> enter your user name and your password
-> enter the following commands exactly as posted (a space at the wrong place and you could erase your system!):

sudo -i [Return] (and your password again -> user name should be "root" after that)

cd /home/name_of_your_user_account [Return]

rm -r .cache/* [Return]

exit [Return] (user name should be "name_of_your_user_account" again

exit [Return] (once again - to log out from your user account on this tty)

-> press [Ctrl] [Alt] [F1] -> you should see the graphical log in screen (SDDM) again -> log in with your user account

This log in could take little a bit longer than normally, because some caches have to be generated again now.

[greenster]

I made edits and added additional info to my previous post https://www.kubuntuforums.net/forum/...463#post691463



Is Dolphin configured to show previews for any file size?

...Yes, that's how it's set up.

[life0riley]

I made edits and added additional info to my previous post https://www.kubuntuforums.net/forum/...463#post691463

Were any of the files created saved with the wrong extension? In other words, a .png saved as a .jpg?

Is Dolphin configured to show previews for any file size?

[life0riley]

I'm a little stumped here. After web searching I found https://forum.manjaro.org/t/dolphin-...-images/116524, but this post is almost 4 years old. I tried to duplicate this by changing the extension, but that didn't work. [Edit: I only change .png to .PNG, but that is the same file type.]

[Edit: This works if you change the extension on the image file to the wrong type. Example: Changing a .jpg to a .png. I was able to duplicate it by doing this.]

[Additional info] Another way to prevent file previews from showing: Configure Dolphin --> Interface --> Previews tab Local Storage. If the number set here is smaller than the file size, the preview will not show. I was able to demonstrate this. Is this local storage number set to files of any size?

Maybe someone with more knowledge of this can jump in here.

[greenster]

‘Show previews’ was not disabled. Only images created since the upgrade are not displayed; older ones, which I created using Kubuntu 25.10, are visible.

[life0riley]

Did Dolphin settings get reset to default with the upgrade? If so, previews may have been unchecked.

Check Show Previews
View --> Show Previews

If you don't show the menu bar displayed
Hamburger icon --> More --> View --> Show Previews

[greenster]

Since upgrading to Kubuntu 26.04 LTS, images that I add to Dolphin via screenshot or have downloaded are no longer displayed. This issue did not occur in Kubuntu 25.10.

How can I fix this issue?