Picasa no longer exists as a supported product. It certainly does exist "out there" in it's last iteration (version 3.9.140) and is still used by a lot of people (including myself) on their machines as a strictly local photo organizer. All of the direct connections to the Google cloud storage are dead and gone, but that doesn't mean that it's not incredibly useful just for use "at home on my own machine."
I have no doubt that what you say occurred did occur, but it's not relevant to the issue the OP presented. As far as I can tell Picasa doesn't touch a single thing as far as the original photos on my hard disc drive and never has (unless I intentionally delete from within Picasa, which I seldom do).
I have archived Picasa versions 3.8 (from 2010) and 3.9 (from 2012) on my Google Drive since various clients still want it with some regularity. Just don't click on the Google Pictures button in version 3.9 (and I have no idea if it would even work anymore).
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
Memory is a crazy woman that hoards rags and throws away food.
~ Austin O'Malley