code: def test_jpeg_dpi():
      # Check that dpi is set correctly in jpg files.
      plt.plot([0, 1, 2], [0, 1, 0])
      buf = io.BytesIO()
      plt.savefig(buf, format="jpg", dpi=200)
      im = Image.open(buf)
      assert im.info["dpi"] == (200, 200)
  
imports: import io
  import numpy
  from numpy.testing import assert_array_almost_equal
  from PIL import Image, TiffTags
  import pytest
  from matplotlib import collections, patheffects, pyplot, transforms, rcParams, rc_context
  from matplotlib.backends.backend_agg import RendererAgg
  from matplotlib.figure import Figure
  from matplotlib.image import imread
  from matplotlib.path import Path
  from matplotlib.testing.decorators import image_comparison
  from matplotlib.transforms import IdentityTransform
label_desc: Use image node_id 8 for calling a global function with example usage: test_jpeg_dpi() without return types