This is only an issue with a single photo or low sample sizes. In the case of family photos, you’d like have a whole bunch of them to reference and could spot inconsistencies more easily. If it becomes so good to be completely indistinguishable from reality, then not sure what the gripe is. You could just as easily think of all pictures as unaltered. It’s a matter of optimism/pessimism or perhaps red pill/blue pill.

Granted, if your grandparents are showing you their vacation pictures from their world travels that never happened, this is a different scenario that is weird and can could happen. It’s a balance of trusting nothing you see while making a few exceptions for your family and whatnot

> If it becomes so good to be completely indistinguishable from reality, then not sure what the gripe is.

Being 100% convincing doesn't make it true. Not being able to tell what's true from what's fake is a self-evident problem. It means you're at risk of forming an invalid view of the world. The only safe approach would be to never believe anything, at which point we've even lost recent history. Madness lies that way.