One idea would be to scan one or multiple folders for duplicates. This would be helpful in saving unnecessary storage space. Another interesting option would be to add only new photos during the backup process.
Hi, CopyTrans Studio will not create duplicate if you backup your device in the same folder. However, it will not be the case if you backup in two or more different folders. You can use the setting "Only backup photos taken from XXX to XXX" to avoid duplicates.