Not LLMs, but locally running facial and object recognition models on your phone's gallery, to build up a database for face/object search in the gallery app? I'm half-convinced this is how Samsung does it, but I can't really be sure of much, because all the photo AI stuff works weirdly and in unobservable way, probably because of some EU ruling.
(That one is a curious case. I once spent some time trying to figure out why no major photo app seems to support manually tagging faces, which is a mind-dumbingly obvious feature to support, and which was something supported by software a decade or so ago. I couldn't find anything definitive; there's this eerie conspiracy of silence on the topic, that made me doubt my own sanity at times. Eventually, I dug up hints that some EU ruling/regs related to facial recognition led everyone to remove or geolock this feature. Still nothing specific, though.)