code: def _compare_image_png(baseline, fig, tol=0):
      import numpy as np
  
      diff = (np.abs(baseline - fig)).sum()
      if diff <= tol:
          return False
      else:
          return diff
  
file_path: python-igraph/tests/drawing/cairo/utils.py
imports: from pathlib import Path
  import sys
  import inspect
  import functools
  from igraph.drawing import find_cairo
label_desc: Use image node_id 7 for calling a global function with example usage: _compare_image_png(baseline, fig, tol) and returns: False, diff