You are conflating two different aspects.

Live Photo is a feature where it captures a couple of seconds of video before/after the photo is taken. From the article that feature was not enabled.

The computational pipeline is where you press the shutter and it blends a few frames together in order to do focus stacking, HDR etc. Based on what I have tried with my iPhone it is doing this in < 100ms which is not enough time to produce these sort of artefacts.

Couldn't it be using frames from before the shutter was pressed? Could the processing take longer when people\animals are in the frame?

Absolutely. But only about less than like 100ms worth at best.

The total latency of shutter + computational photography + save to disk is not greater than the time between her moving from one pose to another.

So the artefacts you would expect to see if this whole pipeline was out of sync was both poses stitched on top of each other in the mirror. Not multiple ones in different mirrors. And definitely not with the whole image as clean as this.

maybe? you can also turn your iphone off, but it still broadcast btle and cell signals. who knows what any feature toggle does anymore, let alone on/off. lol do-not-track is tracked.

You can tell because of the type of file that gets saved in your photo library.

Live Photos are clearly marked.

why are they not marked as video?

Because they’re photos, with a bit of video added for effect when you’re scrolling through them.

is that not just a video with a still frame?

Videos are recorded at 4K/8MP. Photos up to 48MP.

No, they're regular photos, with some lower-quality video added for context.

Because you can share them as photos and the composited image can be shared to the recipient.

Cell signals use way too much battery to be sending them with the phone turned off.