konqueror has 'thumbnail? ( $(add_kdebase_dep mplayerthumbs) )', but dolphin and digikam have: thumbnail? ( || ( $(add_kdebase_dep ffmpegthumbs) $(add_kdebase_dep mplayerthumbs) ) ) video? ( || ( $(add_kdebase_dep ffmpegthumbs) $(add_kdebase_dep mplayerthumbs) ) ) ffmpegthumbs works fine for me with konqueror, but it seems better to remove thumbnail USE and deps from konqueror because it is able to use them only when dolphin is installed. P.S. Please make mplayerthumbs optional in kdemultimedia-meta, ffmpegthumbs works much better and faster then mplayerthumbs with phonon+gstreamer backend.
Both make sense and have been done.