As per Google's blog post, deleting an image/video from Drive will not delete it from Photos. But this doesn't mean deleting the Google Photos folder is safe. If we delete it, then files inside Google Photos which were un-supported media types(by Google Photos) at the time of uploading will be deleted forever!
For example, I have uploaded several files from my PC to the Google Photos folder in Google Drive before July 2019. Some of them, especially PNG files were not synced to Google Photos. Maybe they were unsupported.
What is the easiest way to identify such files? So that I can move them outside of the Google Photos folder and delete the folder?
Tried this filter, but did not work. It works on the filename, not the actual type.
-type:folder AND -".jpg" AND -".gif" AND -".mp4"
This would be nice, if Google could provide a toggle-switch to hide/unhide Google Photos from Drive. If we hide, this will not hide non-synced files(PNG,PDF etc). Then we can do whatever with those file.
Best Answer
This is a good question. It would require being able to create a list of the (filenames of the) photos in Google Photos, and comparing that list to the photos you have in Google Drive.
I can point out other useful information (which doesn't answer your question directly). Firstly, I think that if you synced Google Drive with Google Photos before July 2019, it did not matter which folder in Google Drive the photos were uploaded to. In fact, I think the Google Photos folder in Google Drive only displayed the photos that were directly uploaded to Google Photos (e.g. via a mobile device), and did not duplicate photos that were synced with Drive.
Secondly, the storage space taken up by photos in Drive and Google Photos, with this sync system, was not duplicated. Also, when Drive and Photos were separated, the storage space was not duplicated (just for the existing photos). That means that you will not save storage space by deleting those photos in Drive which used to be part of the sync system (that may change your motivation for deletion).
Personally, I used to upload photos to folders in my own photograph folder system in Google Drive. I've just left them there (as, you've pointed out, that sorting out thousands of photos would be difficult). Nowadays, I still upload batches to Google Drive, with the sync client, when it will take up a large amount of storage (and hence in those cases, uploading directly to Google Photos through the website may be unstable); but, I then delete the photos in Google Drive after importing them to Google Photos. So, what I'm saying is that nowadays I do the deletion every time I use Google Drive in this way, so the task of sorting it out is not left for later on. I understand that saying this in hindsight is not helpful, but it is a suggestion for future behaviour, under the post-July 2019 system.