Paint In 3D ✍️ Paint In Editor✏️ Paint In 2D

Another quick question: (sorry)
I am using this script to save an image to the device gallery:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class savetogallery : MonoBehaviour {

public Texture2D myTexture;

    // Use this for initialization
    public void saveitman () {
   
    NativeGallery.SaveImageToGallery( myTexture, "GalleryTest", "My img {0}.png" );
       
    }
   
}

(This seems to be working a lot easier than the other assets I have tried)

How do I access the ‘painted’ texture to save it to the device gallery?