Booksy's photo guidance is advisory rather than numeric: JPEG or PNG format, high resolution, well lit and in focus, with a warning that images that are too small look distorted or pixelated on your profile. It asks for at least three portfolio photos to get started, and it wants cover and workplace photos shot landscape because those placements are wide. That leaves the actual sizing decision to you, which in practice means the wrong default wins — full-size camera exports that load slowly on mobile search results, or heavy social-media resaves that break down at the pixel level the moment a client zooms into a fade. The middle path is a moderate resize plus a quality pass that holds texture. Portfolio photos are judged close-up, so a long edge around 1600 to 2000 pixels is enough for any phone display while cutting most of the weight out of a 12MP capture. Cover photos are the exception: they render wide, so keep them landscape and do not crop a portrait shot into that slot. Skwish resizes, converts between JPG, PNG and WebP, shows the before and after per file, and packs the whole set into one ZIP for upload. Booksy publishes no hard per-file size cap, so the target here is fast loading and clean detail rather than a platform limit.