Currently the indexed search tags have a hard-coded value named exists but it could be something else, (if deemed useful at search time) tags related to image recommendations could be more granular by including the kind as separate tags.
At query time this would become (suggested syntax): hasrecommendation:image=istype-depicts.
- hasrecommendation:image>0.8 && -hasrecommendation:image=istype-depicts could filter recommendations with a score above 0.8 and without a istype-depicts kind.