Move photos or videos to trash. If you move items to trash while you have back up & sync turned on, those items will show up in trash on every device that syncs to your Google Photos library. They stay in your trash for 60 days and then are permanently deleted.
Open the Google Photos app .
At the bottom, tap Photos .
Touch and hold a photo or video you want to move to trash.
Select other items you want to move to trash.