I don't know, please elaborate. The difference could also be that for a fresco the statue of limitations has expired? Or that the descendants of the "victims" have probably mixed with the descendants of the painters so that it is impossible to find out who should pay who.
Perhaps you mean that the difference is that a fresco is art, but a photograph can't be art? In that case I imagine many photographers would disagree. I also imagine that you would disapprove of naked children on a fresco if that fresco were created today.
My most charitable interpretation would be that the difference has something to do with cultural relativism. That the frescos that have existed for hundreds of years are acceptable because they were made in a time when not all nudity was considered sexual, kind of like we don't hate the ancient Greeks for pederasty even though it would be frowned upon in modern times. But now we know it's wrong and child abuse. If that is true then why don't we point to these frescos as a dark point in human history, like with slavery?
Essentially, a photograph is a near perfect capture of an individual. A fresco is a stylized representation of an individual. I an not saying photography isn't art. But rather, culturally, people are more willing to accept an abstract representation of a nude child rather than a photograph of one. I assume, because, people don't see the fresco as 'real' as a photograph.
I'm sure cultural relativism plays a part, too. If something looks like a renaissance painting people are primed to accept it as art.
Perhaps you mean that the difference is that a fresco is art, but a photograph can't be art? In that case I imagine many photographers would disagree. I also imagine that you would disapprove of naked children on a fresco if that fresco were created today.
My most charitable interpretation would be that the difference has something to do with cultural relativism. That the frescos that have existed for hundreds of years are acceptable because they were made in a time when not all nudity was considered sexual, kind of like we don't hate the ancient Greeks for pederasty even though it would be frowned upon in modern times. But now we know it's wrong and child abuse. If that is true then why don't we point to these frescos as a dark point in human history, like with slavery?