Headroom back, proportions kept
A portrait shot too tight clips the crown of the head or the feet. Uncropping grows the frame in that direction and fills the new band from the surrounding wall, sky or floor, so the person sits comfortably again with their proportions untouched.
Anchor the photo to the top to grow headroom, or to the bottom to add floor — the control is in More options, and the whole picture is always kept.
Questions
Does my photo get uploaded?
No. The picture is read, grown and encoded by code running in this browser tab. It is never sent to a server — there is no server to send it to. The only download that ever happens is the optional edge-painter model, which travels one way, from our model file server to you.
Can it rebuild the actual top of someone's head?
It builds a plausible continuation of the hair and background, not the real missing pixels — those weren't recorded. On plain backgrounds behind a head it looks natural; judge the result before you rely on it.
What if the background behind the head is busy?
Use the edge painter for a continued scene, or the blurred backdrop for a soft, honest fill that doesn't pretend to detail that isn't there.