error share png image (which I take from firebase) and put in an imageview

The following happens. I have a share button, when I try to share an image from inside my drawable, beauty it will, now when I try to share the image that came from firebase, there will not " it closes the app" PS: I am beginner, I know it is because of the image, pq with the local image it will, just do not know how to solve. Thank you right now, for the people who try to help me

HERE I DO THE LOADING OF THE FIREBASE IMAGE INTO A IMAGEVIEW:

 btnFrase = (Button) findViewById(R.id.idBtnLoadPhoto);
    btnFrase.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Log.i("IMAGEM", "Aqui carrega imagem");
            Glide.with(getApplicationContext()).load("https://firebasestorage.googleapis.com/caminho da imagem").into(img);
        }
    });

HERE IS THE SHARE METHOD:

private void sharedImage(){
    // Vamos carregar a imagem em um bitmap
    Bitmap b = BitmapFactory.decodeResource(getResources(), R.id.idPhoto); //idPhoto é o ID da minha imageView
    Intent share = new Intent(Intent.ACTION_SEND);
    //setamos o tipo da imagem
    share.setType("image/png");
    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    // comprimomos a imagem
    b.compress(Bitmap.CompressFormat.PNG, 100, bytes);
    // Gravamos a imagem

    String path = MediaStore.Images.Media.insertImage(getContentResolver(), b, "testetituloimagem", null);

    // criamos uam Uri com o endereço que a imagem foi salva
    Uri imageUri =  Uri.parse(path);
    // Setmaos a Uri da imagem
    share.putExtra(Intent.EXTRA_STREAM, imageUri);
    // chama o compartilhamento
    startActivity(Intent.createChooser(share, "Selecione"));
}

ERROR ON ANDROID MONITOR

10-20 17:10:47.906 3652-3652/br.com.quanticoapps.frases E/AndroidRuntime: FATAL EXCEPTION: main
                                                                      Process: br.com.quanticoapps.frases, PID: 3652
                                                                      java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.graphics.Bitmap.compress(android.graphics.Bitmap$CompressFormat, int, java.io.OutputStream)' on a null object reference
                                                                          at br.com.quanticoapps.frases.MainActivity.sharedImage(MainActivity.java:152)
                                                                          at br.com.quanticoapps.frases.MainActivity.checarPermissao(MainActivity.java:176)
                                                                          at br.com.quanticoapps.frases.MainActivity.access$000(MainActivity.java:34)
                                                                          at br.com.quanticoapps.frases.MainActivity$2.onClick(MainActivity.java:72)
                                                                          at android.view.View.performClick(View.java:5610)
                                                                          at android.view.View$PerformClick.run(View.java:22265)
                                                                          at android.os.Handler.handleCallback(Handler.java:751)
                                                                          at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                          at android.os.Looper.loop(Looper.java:154)
                                                                          at android.app.ActivityThread.main(ActivityThread.java:6077)
                                                                          at java.lang.reflect.Method.invoke(Native Method)
                                                                          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
                                                                          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)