Pixel 3 and Google photos

It would seem to me that this would only affect photos that were downloaded to the phone from some other site, not taken with the phone's Camera (unless the Camera somehow saves its photos via the Download directory, which wouldn't make any sense).
 
It would seem to me that this would only affect photos that were downloaded to the phone from some other site, not taken with the phone's Camera (unless the Camera somehow saves its photos via the Download directory, which wouldn't make any sense).

That's a very interesting observation. Pretty sure the ones being deleted were downloads, though I never use a file manager to delete downloaded pictures. I keep certain downloaded pics and gifs to use on Facebook in comments. I can't be certain that is the case. but it appears spot on. Now the question is why? I have turned Smart Storage off. Currently the largest use is Other Apps and System on my phone. In other apps I do not have a reference to downloads to view. Actually, downloads is under Photos and Videos under sub view Images where all the photos are. So Google recognizes these as photos and uploads them in Photos but for some reason later deletes them from the phone. This sounds like a bug. At first I thought maybe they do not want to house my other images and take up server space. But if that were the case, why are they getting automatically uploaded? Why not only auto upload camera photos and video. That would be perfectly acceptable.

Did you get a change to look at my Google Support link? Do you have any idea what the poster of the Recommended Answer was talking about? I have no clue.
 
Yeah, I did look at that link, and the recommended answer was too technical for me. The general gist that I understood is that downloaded files (handled by the Download Manager) get flagged somehow by the system, and that flag ultimately makes them liable to be deleted automatically at some point.

The Download directory shouldn't automatically backup photos to the cloud unless you manually turned that on in the Device Folders section of the Google Photos app -- is that the case?

Here's an idea for a test -- instead of downloading the images directly to your phone, try downloading them to your computer, and then copy them via USB to a directory separate from /Download (like /Pictures). Then see if those photo files ultimately get deleted automatically at some point. Since these files wouldn't have been managed by the Download Manager, they wouldn't have any potential flag added by it.
 
"The Download directory shouldn't automatically backup photos to the cloud unless you manually turned that on in the Device Folders section of the Google Photos app -- is that the case?"

Yes, I have that syncing as well.

Your idea of a test is good, but even if that works I would not want to have to do that every time I download a picture.
 
Ok, then try this instead -- turn off the cloud backup for the Download directory, and when you download a photo that you want backed up to your cloud, make a habit of moving the photo to the /DCIM/Camera or /Pictures directory. Maybe the bug happens if you set the Download directory to backup automatically?