Apple is known to start enforcing broad rules in new ways without notice. Unless they've made a positive statement confirming that such photos are allowed (I don't know, seems unlikely), I would assume that it's possible for Apple to turn on a nudity classification ML on everyone's photos tomorrow and ban anyone that matches just like Microsoft. I also think that Apple seems to respect user privacy / rights better than Microsoft (though not so much developers). So you might say it's unlikely, but my point is that it's possible; act accordingly. Is it your personal account and you have a backup and you don't think the risk is worth the hassle? Sure, do whatever you want. But is this Apple account even associated with the developer account of an app that makes your living? I would think twice.
For example, did you use the same album each time? Did you both uploaded to the album or only her or you? Did you keep the previous photos in the album? How'd you feel seeing yourself in the album?
Curious as I've never heard anyone shading albums ... Makes sense of course.
To the best of my knowledge the only thing Microsoft searches for and actions in user uploaded files is content that hits against PhotoDNA. https://www.microsoft.com/en-us/photodna
10-20 years ago it was pretty normal to keep and show off nude photos of your kids. I've seen plenty of nude photos of my friends from "a heatwave in the garden + paddling pool" when they were a toddler.
There's nothing sexual or nude about it unless you want to make it that way. For 99.x% percent of us, having one of two genders is as universal as it comes...
The practice finding its way into the modern cloud is completely unsurprising.
let me point out that PhotoDNA can't check a woman's drivers license, and getting shut out of your account because you love an A cup is pretty dismal stuff.
YET ANOTHER feature that is linked to ONE SINGLE account. If apple decides to block your account, everything is gone. This happened some time ago to my microsoft account - everything gone. And why? Because I have uploaded (automatically) a nude picture of my gf to their cloud, it was detected by their algorithm and my account was locked.
I had to communicate with microsoft by a PAPER LETTER(!) to understand WHY my account was locked in the first place and that they would not care to unlock it.
This happened 3 years ago. Their policy might differ today regarding nude content. But for me it was a shock and a lesson.