Upload a normal image, get back a JPEG with a Rec2020 + PQ ICC profile embedded.
No pixel changes — only the tag.
APP2 segment carrying an ICC profile named
Rec2020 Gamut with PQ Transfer — the same profile Apple's systems stamp onto real HDR photos.
Any screen that supports HDR compositing will render the bright regions of the image far beyond
your display's normal brightness ceiling — even though the underlying pixel values never actually changed.