[mazlix]

I don't know exactly what you mean by "post-truth", but I think for the vast majority of human history we've lived in a time where it was rare to have easy/cheap to create and hard to fake records of what happened (photography, videos, audio recordings).

In terms of a single photograph though that's been very easy to fake in compelling ways for at least the past 30 years look at lochness and bigfoot photos.

Video's harder, but still pretty much all of this is not horribly difficult to fake. We've long been able to edit things out and mix audio to make a compelling video of a cartel leader meeting with them, no need for deep fakes.