code: def test_readonly_save(self, tmp_path):
      temp_file = str(tmp_path / "temp.bmp")
      shutil.copy("Tests/images/rgb32bf-rgba.bmp", temp_file)
  
      with Image.open(temp_file) as im:
          assert im.readonly
          im.save(temp_file)
  
imports: import io
  import os
  import shutil
  import sys
  import tempfile
  import pytest
  from PIL import Image, ImageDraw, ImagePalette, UnidentifiedImageError
  from .helper import assert_image_equal, assert_image_equal_tofile, assert_image_similar_tofile, assert_not_all_same, hopper, is_win32, mark_if_feature_version, skip_unless_feature
label_desc: Use image node_id 15 for calling the TestImage obj's underlying member method code with example usage: obj.test_readonly_save(tmp_path) without return types