Simple thumbnailers?

[David Nečas]

Hello,

does any standard possibility exist to register simple specialised
thumbnailers that just run a program to create the thumbnail?

E.g. something like the

[Thumbnailer Entry]
Exec=...
MimeType=...

files that appear to work in Gnome3 (but that I cannot find actually
specified anywhere)?

I have looked at the only implementation of
org.freedesktop.thumbnails.SpecializedThumbnailer1 I was able to find,
maemo-video-thumbnailer.  IMO if you let people not understanding D-Bus
and thus not knowing what they are doing (such as me) implementing this
kind of stuff it can only lead to disaster...

Thanks,

Yeti