convert numpy images to zip

images_to_zip.py

import os
import zipfile
import numpy as np
import cv2


def images_to_zip(images: list, out_filename: str):
    if os.path.exists(out_filename):
        print('File', out_filename, 'already exists. Abort.')
        return
        
    with zipfile.ZipFile(out_filename, 'w') as f_zip:
        for i, image in enumerate(images):
            assert isinstance(image, np.ndarray)
            
            name = str(i)
            image = cv2.imencode('.png', image)[1]
            f_zip.writestr(name + '.png', image)

read_images_from_zip.py

import io
import zipfile
import numpy as np
import cv2


def load_images_from_zip(filename: str, cachemem: bool = False) -> list:
    if cachemem:
        with open(filename, 'rb') as f:
            filename = io.BytesIO(f.read())
    
    images = []
    
    with zipfile.ZipFile(filename, 'r') as f_zip:
        names = self.file.namelist()

        for name in names:
            buffer = np.frombuffer(f_zip.read(name), dtype='uint8')
            image = cv2.imdecode(buffer, cv2.IMREAD_GRAYSCALE)

            images.append(image)
          
    return images