Buried in my “stuff” is my British passport from when I was 5 months old. I could see assorted customs authorities wanting a more up-to-date photo.
My 17.8 year old son, with a full shaggy beard, traveled with me using his 13 year old passport, from before puberty. Rather to my surprise, the official looked at it, looked at him, and waved him on.
If you look deep into the State Department’s website, there’s a page that says something to the effect that “You do not need to get a new passport for your child just because his or her appearance has changed as the natural process of aging.”
Yeah, i wouldn’t have been surprised that they accepted a baby picture for a five year old, because basically, the parents are responsible. But i was a little surprised given that he looked like he could have been 20. But i suppose that’s a really common situation.