#2 existence of kfmclient not checked

[Toby]

It looks like kfmclient is needed for some operations,
e.g. previews, but not listed as a requirement.

On KDE desktops kfmclient is likely to be installed.
But on non-KDE systems (Gnome/XFce/plain WM) it's
rarely installed by default. Installing Kommander
doesn't imply the existence of kfmclient.

How about checking for kfmclient and providing fall-back
tools for non-KDE systems ?

I'd suggest using xine for mpeg preview, because it's
used for DVD preview anyway.

Checking for kview as an alternative png preview tool
and listing "kview OR kfmclient" as a basic requirement
would help, too.

Generally, a config page listing tools used for txt,
png,mpeg and dvd preview would provide the most
flexible solution. Auto-detecting a valid tool for each
category from a list of possible alternatives would be
a premium solution.