[zozbot234]

Just use PNG: https://www.w3.org/TR/png-3/ (for HDR content, see the cICP, mDCV and cLLI chunks; also note that PNG supports up to 16-bit channel depth out of the box).

[jiggawatts]

PNG encoding a 16-bit HDR photo from my old camera needs about 150 MB, from the new camera they're something like 220 MB.

That's a size of a 30 minute TV show for a single happy snap.

Not exactly user-friendly for sharing in a text message.