Launch the GooglePlus app and go to the home menu and tap the gear next to your photo. On the settings page select Camera and Photos. In the camera and photos settings menu turn off ‘Auto Backup.’. That about does it you will not have to worry about Google Plus skagging your photos without your explicit permission.How do I turn off Google Sync?
To turn off the sync for the one account, make sure that's the account you're signed in to. Then go to Drive (drive.google.com) and click on the gear icon at the top right. Select Settings and UN-check the box for offline syncing. Next, sign out of that account and into your other account.