By default, KDE’s file manager Dolphin will display thumbnails for images but not for other file formats, like PDFs and videos. In a few steps you can enable thumbnails for those formats.

Install the required packages

Install these packages using your system package manager (apt, pacman, etc.):

  • Videos: ffmpegthumbs
  • PDF, PostScript, DVI: kdegraphics-thumbnailers

Change Dolphin settings

Go to Dolphin, click on the three-bar menu and select Configure -> Configure Dolphin.... On the General section, select Previews and check Video files (ffmpegthumbs) and/or PostScript, PDF and DVI Files. Click OK to save the changes.

Dolphin settings