I have turned off previews for all types of files in Dolphin > Settings > General > Previews as I want my folder views to be uncluttered and the icon to represent the file type. However I use the Information pane only for getting more details about a given file. Hence I would prefer to see file previews in that pane. This is currently not possible because the Information pane follows the same settings for previews as the main folder view. Right-clicking on an empty part of the Information pane gives a checkable Preview option but if the main Preview settings is turned off then turning this on only gives the mimetype icon in big size which is not useful. I think it would be appropriate to consolidate and streamline this behaviour. My suggestion is: 1) Under Settings > … Previews change “Show previews in the view for” to “Show previews for” 2) Create a frame titled “Show preview in” containing two check boxes “folder view”, “info pane”. This lets people select the behaviour they want. The right-click Preview option in the Info pane should either be removed or linked to the corresponding option under Settings as above. Just displaying the mimetype icon in big size is pointless and should not be done when preview in the info pane is disabled. I am using Dolphin 21.12.3, KDE 5.92.0, Qt 5.15.3, all default available on Kubuntu Jammy.
Just now had an opportunity to boot up my earlier Kubuntu Focal release (Dolphin 19.12.3, KDE 5.68.0, Qt 5.12.8) and noticed that it had this behaviour just as I personally wanted: in the information pane if preview is enabled then it shows the full preview even though in the folder view all previews are disabled. As far as I am concerned, the same behaviour can be restored. That is, the preview in the info pane if enabled should always be an actual preview and not just the mimetype icon in big size, and the preview settings under Dolphin settings must be for the folder view only. I had only made the earlier suggestion in the interest of more configurability for others who may prefer otherwise.
It makes sense. If you don't have thumbnails on the files, you might still want to see the preview when you re deliberately seeking out more information about it.
In Dolphin 22.04.3, I get separate previews in View and Information. I have set a keyboard shortcut for Show Preview (which controls only previews in View), and this is separate from the Preview checkmark in Information. I can have previews off in the view (so I see just icons), but on in Information (so I see e.g. image previews).
To make the bug clear: It would be nice if the preview settings in General > Previews did not affect the Information Panel. To be clear, this would be very easy to change. But it would hurt other users that may want absolutely no previews for certain file types. The alternative would be having two options seem to me way overkill. Our goal is not to please everyone every specific need but to compromise to cover as many use cases with as less as possible complications. To me, this seems like a Resolved > Intentional