  import time
  
  from functools import partial
  
  import cv2
  import numpy as np
  
  import tensorflow as tf
 
</s> remove from hashlib import sha1
 </s> add from zlib import crc32 </s> remove from lib.align import Alignments, AlignedFace, DetectedFace
from lib.image import FacesLoader, ImagesLoader, ImagesSaver
 </s> add from lib.align import Alignments, AlignedFace, DetectedFace, update_legacy_png_header
from lib.image import FacesLoader, ImagesLoader, ImagesSaver, encode_image </s> remove from lib.align import Alignments, AlignedFace, DetectedFace, get_centered_size
from lib.image import read_image_hash_batch
 </s> add from lib.align import (Alignments, AlignedFace, DetectedFace, get_centered_size,
                       update_legacy_png_header)
from lib.image import read_image_meta_batch
from concurrent import futures
  import time
  
from concurrent import futures
  from functools import partial
  
  import cv2
  import numpy as np
  
  import tensorflow as tf
keep add keep keep keep keep keep keep
 Update extracted faces to use PNG EXIF data (#1123)

Documentation
  - Update Usage.md, align.rst and image.rst
lib.image.py
  - read_image - Remove hash return, add metadata return
  - Remove read_image_hash functions
  - Add read_image_meta functios
  - Replace encode_image_with_hash with encode_image (to store metadata)
  - Add png meta reading and writing functions
  - Update Image Loaders/Savers to handle metadata rather than hashes
lib.training_data
  - Naming updates to remove references to hashes
lib.align.Alignments
  - Add versioning notes
  - Increment alignments version to 2.1
  - Deprecate hashing lookup functions
  - Replace filter_hashes with filter_faces
lib.align.detected_face
  - DetectedFace
    - Remove hash property
    - Add png header data serializing/deserializing functions
  - Mask
    - Add png header data serializing/deserializing functions
  - add update_legacy_png_header function to update png meta data
lib.cli.args - Deprecate alignments files for training
- plugins.train.trainer
  - Update alignments/mask code to read png header data
- scripts.convert
  - Aligned images folder - read data from png headers
- scripts.extract
  - Write png header information and no longer store hash of face
- tools.alignments
  - remove leftover-faces, merge and update-hashes jobs
  - Update jobs to use png meta data rather than hashes
- tools.manual
  - Update extract code to output png meta data and don't store hashes
  - Perform check on launch that tool is not pointing at a faces folder
tools.mask
  - Update to use png meta data
tools.sort
  - Update to use png meta data 
plugins/train/trainer/_base.py