This only affects future media, not past saves
The toggle applies going forward only. Photos already auto-saved remain in your gallery, so you'd need to manually delete previously saved images if you want to clear them out too.
The setting is per-device, not per-chat
On most apps this is a single global switch covering every conversation, rather than something you configure chat by chat. Turning it off once cleans up all your chats at once, instead of needing to repeat the change for each contact or group.
Frequently Asked Questions
Does turning this off delete photos already saved to my gallery?
No, it only prevents new incoming media from being auto-saved going forward -- anything already in your gallery stays there until you delete it yourself.
Will I still be able to see photos inside the chat after turning this off?
Yes, photos still appear and can be viewed or manually saved inside the conversation -- the toggle only stops the automatic copy to your gallery.