I would like to know if the Save Incoming Media feature in Whatsapp create duplicates i.e. saved in both Whatsapp application data and also Camera roll?
2 Answers
Yes, it does duplicate media in the sense you describe. With that switch activated, all incoming images will have 2 copies: one on the app and one on the Camera Roll.
To answer your comment, not so much the ability to auto-delete, but switching it off prevents it from being copied to Camera Roll - you'll have to manually delete the message in order to delete the media.