PD, particularly for visual works, is something people often think is the case, but really isn't. It's not possible in a number of countries to give up copyright. In others, even when you can, you have moral rights.
If you are using PD for visual works, you might as well just tell people they can't use it.
So, what status does IP have when its copyright expires?
In particular, something taken during our lifetime will almost certainly not become public domain until well after we are dead.
It's probably also worth noting in this discussion that (as per the referenced link) subjects in the photos may have privacy or publicity rights for photos used for commercial (non-editorial) purposes.
But we’ve heard from our community that we’re missing two important designations: Public Domain and Creative Commons 0 (CC0). Many members of our community want to be able to upload images that are no longer protected by copyright and correctly tag them as being in the Public Domain, or they want to release their copyright entirely under CC0.
So it was odd for you to not mention CC0 at all in your comment.
(I've edited the last paragraph in an attempt to be less abrasive)
They don't seem to be ambivalent about people using it.