savingImageToInternalDrive.java

    private String saveImageToInternalDrive() {
        Bitmap bitmap;
        OutputStream outputStream;

        bitmap = ((BitmapDrawable) mImageView.getDrawable()).getBitmap();

        File filePath = getFilesDir();

        File imageDir = new File(filePath.getAbsolutePath() + "YourDirName");
        if(!imageDir.exists()){
            imageDir.mkdir();
        }

        File imageFile = new File(imageDir, "YourImage.png");

        boolean isSaveSuccessful;

        try {
            outputStream = new FileOutputStream(imageFile);
            bitmap.compress(Bitmap.CompressFormat.PNG, 100, outputStream);
            outputStream.flush();
            outputStream.close();
            isSaveSuccessful = true;

        } catch (IOException e) {
            isSaveSuccessful = false;
        }
        
        if(isSaveSuccessful){
            return imageFile.getAbsolutePath();
        }else{
            return "Failed to save image";
        }
        
    }