I’ve been using Dolphin for quite some time now and it was only recently that I realized that you could fiddle with the Dolphin settings to enable the file manager show previews of files, be it image files, text, videos or even PDF’s. All that you’d require to do is to perhaps install a few custom packages and tweak with the settings in the Dolphin’s “control” panel if you say. This control panel is NOT the one that you might’ve become accustomed to if you’re a windows user. What I mean is this, just a tab at the top of Dolphin.
1. Video/audio files
$ sudo apt-get install kffmpegthumbnailer or $ sudo apt-get install ffmpegthumbnailer
2. PDF documents
$ sudo apt-get install kdegraphics-thumbnailer
3. Image and Text files
These should show their preview when you enable the preview mode in dolphin. You can always lookup in the “configure dolphin” tab of your settings.
Now that you have the necessary packages installed, all you need to do is go to the Dolphin settings which can be achieved by clicking the control menu in the file manager(Dolphin) and make required changes as shown below. You should now be able to preview your files whenever you browse through your files using Dolphin.
This is how my Dolphin configuration looks like after enabling all the required options in the “control” -> “configure dolphin” menu.