code: def test_extents():
      with Image.open("Tests/images/test_extents.gif") as im:
          assert im.size == (100, 100)
          im.seek(1)
          assert im.size == (150, 150)
  
imports: from io import BytesIO
  import pytest
  from PIL import GifImagePlugin, Image, ImageDraw, ImagePalette, features
  from .helper import assert_image_equal, assert_image_equal_tofile, assert_image_similar, hopper, is_pypy, netpbm_available
label_desc: Use image node_id 59 for calling a global function with example usage: test_extents() without return types