That's going to be really confusing when a fully passing trans person goes up to customs or TSA and it's clearly wrong. Although then again my ex had her old picture still and the looks she got were pretty funny (that was decades ago, though, when this wasn't being used as a scapegoat).
This is going to be a problem for trans people exiting the country too. When I got to Britain a few days ago, my passport was scanned by a machine and matched with video of my face inside the booth with the machine. I have a feeling that the machines will have issues if the passport photo shows them presenting as a different gender.
I get that they check the photo, I'm saying that if they're not going to allow you to express your real gender in a passport, they're almost certainly not going to allow you to express it in your passport photo.
presumably with a bunch of failsafes and a tolerance threshold for acceptability. Something like facial hair, makeup, glasses, haircut won't even blip it.