how to update user profile image using firebase and Picasso library

Question

I'm trying to update the user profile image in the Firebase Realtime Database on my application but I'm unable to get the reference of the current user as I declare it in another activity.

My code and database structure is as follows:

profile image

as in this current picture and the code, I'm writing manually the id of the child node (gli) because it is the user_name of the current user in the firebase, please help me how can I give it a path through coding.

code:

private void profileImage(){

        pImageRef = FirebaseDatabase.getInstance().getReference("doctors/doctors_registration/gli/pimage"); 👈👈

        pImageRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {

                String  imageurl=  String.valueOf(dataSnapshot.getValue()) ;
                Toast.makeText(HomeActivity.this, "link:"+imageurl, Toast.LENGTH_SHORT).show();
                Picasso.get()
                        .load(imageurl)
                        .into(profileimg);
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

    }

Please see the screenshot of the database structure and help me how I can get the current user profile image?