Compress File Android Studio

I'm trying to compress my File which in case it's an image but it keeps going with sizes over 4MB someone would know to help me. Here is the code below:

   @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (resultCode == RESULT_OK) {
        if (requestCode == REQUEST_TAKE_PHOTO || requestCode == REQUEST_PICK_PHOTO) {
            if (data != null) {
                // Get the Image from data
                Uri selectedImage = data.getData();

                String[] filePathColumn = {MediaStore.Images.Media.DATA};

                Cursor cursor = getContentResolver().query(selectedImage, filePathColumn, null, null, null);
                assert cursor != null;
                cursor.moveToFirst();


                int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
                mediaPath = cursor.getString(columnIndex);

                // REDUZIR O TAMANHO DO ARQUIVO

                Bitmap bmp = BitmapFactory.decodeFile(mediaPath);
                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                bmp.compress(Bitmap.CompressFormat.JPEG, 50, bos);


                if(imageView == null) {
                    imageView.setImageBitmap(BitmapFactory.decodeFile(mediaPath));
                }
                else if(imageView != null){
                    imageView2.setImageBitmap(BitmapFactory.decodeFile(mediaPath));
                } else if(imageView2 != null) {
                    imageView3.setImageBitmap(BitmapFactory.decodeFile(mediaPath));
                }
                cursor.close();

                postPath = mediaPath;
            }


        }else if (requestCode == CAMERA_PIC_REQUEST){
            if (Build.VERSION.SDK_INT > 21) {

                Glide.with(this).load(mImageFileLocation).into(imageView);
                postPath = mImageFileLocation;

            }else{
                Glide.with(this).load(fileUri).into(imageView);
                postPath = fileUri.getPath();
            }
        }
    }
    else if (resultCode != RESULT_CANCELED) {
        Toast.makeText(this, "Ocorreu um erro!", Toast.LENGTH_LONG).show();
    }
}

Probably something silly but I can not solve it, whoever knows please help me.