Thumbnails not showing in Thunar without F5-ing Dolphin (KDE)

organicode · 2026-05-02 22:40:11

Icons for svg files is only the general icon for *all* SVG files rather than a thumbnail of the image, but if I switch to Dolphin (file manager for KDE) and refresh the folder where the files are, they get the proper thumbnail, in both Dolphin, and after I refresh the tab, in Thunar.

What may be the issue?

ToZ · 2026-05-03 00:10:48

librsvg is required - I gather from your other post its now installed. You can run tumblerd in debug mode, open thunar to a directory with svg files, and see whats output.

organicode · 2026-05-03 05:14:49

ToZ wrote:

librsvg is required - I gather from your other post its now installed. You can run tumblerd in debug mode, open thunar to a directory with svg files, and see whats output.

That's super interesting! And I suddenly feel like a very thorough son-of-gun, for finding a bug related to an exact feature that I'm seeking. No I still don't have it installed, but will now grab it. I hadn't been prompted to get it by apt for any program, including thunar's package for some reason. This is Trisquel's (11.0 aramo) repo, mind.

*goes exploring*

I'm not at the KDE machine, and was going to ask you which dependency of thunar ultimately should pull in librsvg, but I went on debian web binge myself, and found the culprit, libgtk-3-0t64 a dependency of thunar, only lists librsvg2-common as recommended, This would **not** solve my issue wrt not having a CLI (command line interface) to make PNG from SVG because the binary to do that is again not a dependency of the library but only a "Suggestion" (lower importance than "recommendation") in Debian (see librsvg2-2).

Wow though.

My only suggestion would be to have a message in the "Preferences" of Thunar in the "Display" tab under Thumbnail to inform the user, if a call to librsvg fails, "Thumbnail support requires librsvg". On hover a tooltip might read, "List of recommended packages that are currently not installed that relate to Thunar or its dependencies: <LIST_OF_PACKAGES>". Its the only fix I can think of, but requires catering to different package managers(?). I assume that Xfce devs don't want to force thumbnail compatibility on everyone by making librsvg an outright dependency, but surely this use-case (thunar with KDE over debian) is not unusual, and may impact very negatively on users experience when it does happen. Is there a better way to help users?

Last edited by organicode (2026-05-03 05:22:53)

ToZ · 2026-05-03 09:26:54

organicode wrote:

My only suggestion would be to have a message in the "Preferences" of Thunar in the "Display" tab under Thumbnail to inform the user, if a call to librsvg fails, "Thumbnail support requires librsvg".

I'm not sure this is the way to deal with this. There are may other dependencies, especially for tumbler thumbnailing, that you could potentially have a full dialog of messages. The better way to deal with this is through the distro packaging and using dependencies and recommends. But this would be a distro-specific thing.

organicode · 2026-05-09 18:22:10

Yes, I appreciate that ToZ. The plot thickens... or dilutes, or gets stale ... or snaps (haven't worked out which yet)

So I downloaded 'librsvg2-2' and 'librsvg-common' for the KDE Debian (Triskel) Thunar. After traveling back to install it I found those two packages **were** already installed, contrary to what I thought and wrote above (I keep a record of packages I've installed so last week I could only check that list and because they weren't on that list I assumed I hadn't installed them. They must be installed by default in Triskel.

Thanks for mentioning tumbler's debug mode. Last week, because I thought I simply needed to install librsvg2-2, i didn't look into that but now I will. I suspect a bug is stopping the something from working... the version of Thunar in the Trisquel (Aramo) repo is older (at 4.16.10 last I checked) but Thunar was producing thumbnails fine and only recently started failing. Thunar is still using thumbnails from that past time when it worked, such thumbnails must be in a cache, i know these thumbnails were made by Thunar/Tumbler because when Dolphin makes thumbnails they fill the entire possible space for the icon of a file, so even when the image is only 16px, Dolphin (AND thunar IF AND ONLY IF Dolphin made the thumbnail) will enlarge it, or make it fill the entire space. I don't like that which is one of the reasons I prefer Thunar.

So thanks for mentioning the debug mode, is there anything distinct I should look for?

Last edited by organicode (2026-05-09 18:23:19)

ToZ · 2026-05-09 18:52:24

organicode wrote:

So thanks for mentioning the debug mode, is there anything distinct I should look for?

If tumbler has an issues with generating a thumbnail, you will see an error message. It will also list, on its start, what thumbnailers it has identified and which filetypes are associated with that thumbnailer.

organicode · 2026-05-16 20:16:35

Okay, so I worked out that the version of tumbler that Trisquel OS had was a fairly old (4.16) and according to the above link is an unstable(!) version and doesn't even have debugging support yet.

I got tumbler working (sort of) by restarting it (and thunar while at it) *BUT*...

kill -9 $(pidof thunar thunar-volman tumblerd) # the -9 signal was needed iirc
sleep 1         # pause a bit
thunar &        # relaunch thunar. Thumbnails now worked... *BUT*

...the CPU started going absolutely crazy, 'tumblerd' was throttling it to the max. PC was over-heating badly.

I killed the tumblerd process from the KDE tool. And since then the overheating problem hasn't resurfaced, and Thunar works fine and the thumbnails are excellent. I notice that videos don't have those black bars on the sides with white reel holes. Assuming they were added after 4.16.

The age-old trick... of 'turning-thing-off-and-on-again' saed the day, sort of. Well I had to do it twice let's say.

PS. I think the latest release of Trisquel (12.0 Ecne) does(???) have a stable version of tumbler now (4.18.1-1.1build4) from April 2024, so if I'm not mistaken I very much look forward to upgrading now smile

Mystery solved, to an extent.

Answers to above musings welcomed.

Thanks

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#1 2026-05-02 22:40:11

Thumbnails not showing in Thunar without F5-ing Dolphin (KDE)

#2 2026-05-03 00:10:48

Re: Thumbnails not showing in Thunar without F5-ing Dolphin (KDE)

#3 2026-05-03 05:14:49

Re: Thumbnails not showing in Thunar without F5-ing Dolphin (KDE)

#4 2026-05-03 09:26:54

Re: Thumbnails not showing in Thunar without F5-ing Dolphin (KDE)

#5 2026-05-09 18:22:10

Re: Thumbnails not showing in Thunar without F5-ing Dolphin (KDE)

#6 2026-05-09 18:52:24

Re: Thumbnails not showing in Thunar without F5-ing Dolphin (KDE)

#7 2026-05-16 20:16:35

Re: Thumbnails not showing in Thunar without F5-ing Dolphin (KDE)

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