Remove image_utils and PIL reference

CONTRIBUTING.md

@@ -66,7 +66,6 @@ Optional packages to install if you want to run related tests:
   source. Commit `e6eddd80` is known to work.)
 - `unidecode` (dependency for testing text preprocessing functions for examples/pipeline_tacotron2)
 - `inflect` (dependency for testing text preprocessing functions for examples/pipeline_tacotron2)
-- `Pillow` (dependency for testing ffmpeg image processing)
 
 ## Development Process
 

test/torchaudio_unittest/common_utils/__init__.py

@@ -24,7 +24,6 @@
 )
 from .data_utils import get_asset_path, get_sinusoid, get_spectrogram, get_whitenoise
 from .func_utils import torch_script
-from .image_utils import get_image, rgb_to_gray, rgb_to_yuv_ccir, save_image
 from .parameterized_utils import load_params, nested_params
 from .wav_utils import get_wav_data, load_wav, normalize_wav, save_wav
 import pytest
@@ -73,10 +72,6 @@ def inject_request(self, request):
     "load_params",
     "nested_params",
     "torch_script",
-    "save_image",
-    "get_image",
-    "rgb_to_gray",
-    "rgb_to_yuv_ccir",
     "use_deterministic_algorithms",
     "zip_equal",
 ]