New issue by glaubersm on void-packages repository

https://github.com/void-linux/void-packages/issues/12890
Description: ### System

* xuname:  
 Void 5.1.16_1 x86_64 GenuineIntel notuptodate rrFFF
* package:  
kdegraphics-thumbnailers 19.04.2_1
ffmpegthumbs 19.04.2_1

### Expected behavior
thumbnailers always work with Dolphin

### Actual behavior
Dolphin never generates thumbnails of PDF files even if such feature is enabled in Dolphin settings.
Thumbnails of videos files and png files are not generated if such files are located
in Home or in root path of a partition. Dolphin generates the thumbs of the same video and png files if they are located in a folder instead of in Home or root path of a partition
These problems were solved on my system after I install ghostscript package.

### Steps to reproduce the behavior
install Void with KDE Plasma desktop environment
install dolphin, kdegraphics-thumbnailers and ffmpegthumbs packages.
enable preview of videos, pdf and pictures in Dolphin settings
click "View" menu of Dolphin and check "Preview"
store a mkv video, a pdf and a png file in your Home
Result: Dolphin  generates no thumbnail
Now create a new folder in your Home
copy/move the mkv, pdf and png files to the just created fodler and open such folder
Result: now Dolphin generates the thumbnail of all files