Hello. This is my first post. Thank you for letting me in the KDE community. I'm using KDE 4 on Ubuntu.

I found Dolphin is the best file manager in the world. Konsole,shortcut-key and thumbnails greatly help my quick file managing.
Especially I love thumbnails. I always use Preview mode and browse folders that contain images. It is very helpful.

But if I could,I want to get thumbnails bigger so I want to change thumbnails icon size and resolution.
In Dolphin,maximum thumbnail icon size is limited to 256 pixels (it is not enough for me...) and thumbnails resolution can't be changed at all.
So I request the options that allow users to change the thumbnails size and resolution more flexible.

And if anyone knows how to change maximum thumbnail size by hidden option,please tell me how to configure.
Dolphin config text file or so? I googled but found none solutions....

Thank you. Best regards.

I think that the Dolphin/KDE is using the freedesktop.org thumbnail managing specification: http://specifications.freedesktop.org/t ... atest.html

The thumbnail specification '4.1. Directory Structure' is telling:

Normal: The default place for storing thumbnails. The image size must not exceed 128x128 pixel. Programs which need smaller resolutions should read and write the 128x128 thumbnails and downscale them afterwards to the desired dimension.

Large: The previous notes apply to this directory too, except that the thumbnail size must be 256x256 pixel.

Thank you for reply.

Oh. I didn't know that such a core component has limitations on thumbnails size....
That means Dolphin can't make larger thumbnails any way?
OK. I seems to have to make an application by myself....Thank you.

By the way, given that KDE (and maybe,other GNU desktops too) doesn't show larger thumbs,how to get along with Hi-dpi (4K or so) monitors?
I think someday many people would use such a Hi-dpi displays.
If so, icons would be too small and barey visible. Is there a solution for that?
I don't have 4k display yet but I'm worrying about it.

Thumbnailing

The Dolphin is using the KDE 'thumbcreators' to create small preview images (thumbnails). With the KDE4: http://api.kde.org/4.x-api/kdelibs-apid ... eator.html .

Bigger preview picture

Some of the distributions are using patched Dolphin to use the KLook - http://www.koryavov.net/2012/03/klook-n ... -rosa.html .

The OpenMandriva seems to use the Klook as default.



It is possible to install the Klook to the other distributions - with the Kubuntu: https://www.kubuntuforums.net/showthrea ... ok-KDE-4-9


There is also an option to edit the Dolphin code to show the bigger preview picture when the mouse is over an file (video/picture): https://www.kubuntuforums.net/showthrea ... -Konqueror

Thank you for reply.

They are interesting. I'll try them out.
I guess such a beautiful features could be a strong reason to join PC-Linux for Win or Mac users.
These days, almost all of works can be done with a web browser and LibreOffice.
And we can watch videos and listen to musics with free-softwares.
I think more people should use Linux....except gamers....Thank you.

By the way, I found this post.
https://bugs.kde.org/show_bug.cgi?id=328430

This means digikam came to handle its own DB of storing thumbnails.
This could be done in dolphin, maybe? Or dolphin is too cardinal application so this would be a hard work?
I think 512px thumbnails would be needed for UHD or higer dpi environment.
What do you think about it ? I want to hear opinions.

Can the Dolphin use own database for the thumbnails - why not ?

I think that it is a good idea.

There are plenty of examples. Copying from the PhotoQt ( http://photoqt.org ) settings pros and cons of the different thumbnail caches:

Thunbnail Cache

Thumbnails can be cached in two different ways:
1) File Caching (following the freedesktop.org standard) or
2) Database Caching (better performance and management, default option).

Both ways have their advantages and disadvantages:

File Caching is done according to the freedesktop.org standard and thus different applications can share the same thumbnail
for the same image file. However, it's not possible to check for obsolete thumbnails (thus this may lead to many unneeded
thumbnail files).

Database Caching doesn't have the advantage of sharing thumbnails with other applications (and thus every thumbnails has to
be newly created for PhotoQt), but it brings a slightly better performance, and it allows a better handling of existing
thumbnails (e.g. deleting obsolete thumbnails).

PhotoQt works with either option, though the second way is set as default.

Although everybody is encouraged to use at least one of the two options, caching can be completely disabled altogether. However, that does affect the performance and usability of PhotoQt, since thumbnails have to be newly re-created every time they are needed.

And looking the KDE Photo Album ( https://www.kphotoalbum.org ) - The user can freely decide the thumbnail dimensions. The KPhotoAlbum is using own thumbnail database.

Please note that PhotoQt and KPhotoAlbum are dedicated photo management applications - while Dolphin is a file browser. There is quite a difference as a result. Not all thumbnailers would have the necessary support for producing larger thumbnails.

I know, I am reviving this thread back from the grave, but now, in 2021, I would like to add my voice to this request:

Since 2014 technology has evolved. Displays have become 4K by default, high DPI is almost a standard. Especially with that in mind, it would be a great idea to add higher resoluted thumbnail sizes, at least 512x512 ! Or even better: Why not allowing to enter a custom size?

I am a graphic designer myself and I constantly bite my teeth, for not beeing able to get larger thumbnails. Yes, of course I could use my image manager, but it is harshly disrupting a workflow, when constant switching of apps - only to get a larger preview image - is required.

So, I raise my hand for this feature request and say, yup, me too.

HI. knecker.
I'm surprised to see it's already 7 years since I posted this topic!
Like you, I've been using 4K or higher resolution display with KDE for years.
I'm still strongly eager to see bigger thumbs support, actually.

BTW, it looks like the time has come, finally.
Do you know the Thumbnail Managing Standard of freedesktop.org has updated?
Last year they just added x-large and xx-large thumbnail sizes to their standards.
It's the first update in this 8 years!
According to it, chances are we'll see 512x512 and 1024x1024 thumbnails in dolphin in the near future.
Feeling sorry to be a normal user (I mean, not a coder.) so I can't contribute to it.
But I'm really really looking forward to the day!

[url]https://specifications.freedesktop.org/thumbnail-spec/thumbnail-spec-latest.html[/url]

[quote] Normal: The default place for storing thumbnails. The image size must not exceed 128x128 pixel. Programs which need smaller resolutions should read and write the 128x128 thumbnails and downscale them afterwards to the desired dimension. See Thumbnail Creation for more details.

Large: The previous notes apply to this directory too, except that the thumbnail size must be 256x256 pixel.

Extra Large: The previous notes apply to this directory too, except that the thumbnail size must be 512x512 pixel.

Extra extra Large: The previous notes apply to this directory too, except that the thumbnail size must be 1024x1024 pixel. [/quote]