I have Google Photos app enabled to automatically backup all my photos and videos to my Google Photos. My question is, once they are on the drive how can I delete the original from the phone without having it deleted on the Photos?
After the photos have been backed up, in the Google Photos app you can delete the photos by selecting the photos you want to delete and then pressing the three dots in the top right corner and selecting "Delete device copy".
This will delete the copy on the phone, but leave the copy stored online safe.
Adding to Whitebear's excellent answer for deleting photo by photo, there are two other ways.
- You can delete photos from the "Gallery" app and that will delete photos from your device only (though I am unsure of the effect if you set up Photos to display cloud photos in Gallery)
- You can use the "Free up device storage" option under the Settings in Photos - this will go through and delete all synced photos that it can. I believe this is a new option, as I had to update the Photos app to make this available.