How to include additional folders in OneDrive photo backup for mobile?

[Araragi]

So yeah, Lumia 650 and 735 both on Windows 10.
A lot of family pictures are received on those phones via Viber and WhatsApp.
How the heck do I make OneDrive automatically back up those received photos?
On Android I'm simply asked if I want to add a newly created folder to the camera backup. Here it just uploads the photos taken with the phone's camera, nothing else. And there's no setting in the app like on Android to choose what gets uploaded.

 

[libra89]

I don't think that's an option. I'm guessing you might have to open each one, tap save and then save it to OneDrive?