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

[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?

[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]

‘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]

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.

[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?

[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.

[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]

Thank you very much for your help, but I’m afraid I’m stuck here:

[Schwarzer Kater]

These are "single commands" you have to enter - just a moment, I will alter my post accordingly… Please reload this page now.

And no spaces in between where there are none in my post! Enter them exactly as I posted in the commands, please - a space at the wrong place and you could erase your system!
There are single spaces directly behind sudo, cd, rm and -r -> nowhere else.

[jlittle]

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

That's ctrl-alt-f2 on my desktop (with 25.10). ctrl-alt-f1 shows the boot messages.

[greenster]

Schwarzer Kater I’ve now managed to follow your instructions successfully, but now my old images – the ones I created before the upgrade – are no longer visible either.

[Schwarzer Kater]

jlittle :

I was a bit unsure myself, but had tested it before posting.

I have tested this two more times:
SDDM seems always to be on tty1 now, hence [Ctrl] [Alt] [F1].
The GUI is somewhere between tty2 and tty4 after one has logged in.

Don't ask me why, I am confused…
They must have changed something in Kubuntu 26.04 compared to the releases before.

[life0riley]

I had one that was [Ctrl] [Alt] [F7] in one of mine. I can't remember the OS.
I have to step away for an hour, but will be following. I'm interested to see if clearing the cache worked.

[sgmoore]

systemsettings -> default applications -> file associations what does it list for .png?

[greenster]

I haven’t changed anything since I followed your instructions to upgrade to Kubuntu 22.04 LTS.

Is it possible to completely reset Dolphin?