Now I have manually moved the files and I'm wondering whether this is a good idea or whether XnView always uses the /usr/lib/X11/app-defaults path for its configuration file or is there a way to tell XnView that the path should now be /etc/X11/app-defaults?
btw. is there a .deb-packaged version of XnView? I could build a .deb on my own and thus help XnView if I wasn't such a noob in debian package generation

Is there a way that debian puts xnview into its repository? I guess there are some license problems, but they got the contrib for that?