Create folder on device storage, copy images in it

My app is supposed to let the user take photos and then store them in a separate folder.
So far, I can take an image with Camera from ionic-native. The
returns Camera.DestinationType.FILE_URI points to a temp directory (in android). So what I want to do is create an app folder on the internal storage (or the sd card) that stores the images persistently.

How can I do this?