Most (all?) photo apps include a crop function, allowing your mom just crop out everything else.

I hope you’re being sarcastic. If not, expecting someone’s parent to know how to use a photo app’s crop functionality just to communicate an error state is a failure of understanding typical streaming app users.

I wasn't being sarcastic. This is not a case of not being capable of doing something, it's about not knowing the functionality exists. Cropping is very simple. I assumed the GP didn't know about it either or he would have taught his mom already.

Could the manufacturer solve this in a better way? Probably but that won't solve the issue the customer has now.

Poe's Law goes both ways. As a matter of fact, my mom invented digital photo cropping (or "pixel array extent adjustment," because even in her prime she wasn't a marketing genius, bless her heart). We know better than to expect her to submit a bug report once she's settled down to watch TV for the evening.

Jokes aside, "upload a photo of her living room" was meant to highlight the ridiculousness of the UX. I believe the designer of that flow had an OKR to decrease the number of reported bugs.