Just a guess,
but it looks like xdg-open does not know how to open your files.
To see what programme xdg-open uses for a certain file, Try:
xdg-mime query filetype someting.jpg
xdg-mime query default image/jpeg
to get this, in the directory /usr/share/applications/ you need:
the file defaults.list with this entry
and the file geeqie.desktop with the command to start geeqie.