When I try to open something with feh, it will work if the file doesn't have any characters like " or ; or   etc. When I look at rifle.conf I see
#-------------------------------------------
# Image Viewing:
#-------------------------------------------
mime ^image, has feh,    X, flag f = feh -- "$@"
mime ^image, has eog,    X, flag f = eog -- "$@"
mime ^image, has sxiv,   X, flag f = sxiv -- "$@"
mime ^image, has mirage, X, flag f = mirage -- "$@"
mime ^image, has gimp,   X, flag f = gimp -- "$@"
ext xcf,                 X, flag f = gimp -- "$@"

I tried to add " and ' around "$@" but unfortunatley that doesn't work.