use the pillow module to convert all kinds of pictures into pixel sets, then convert them to numpy arrays, and finally save them to a file.

Please refer to the following code

-sharp -*- coding: utf-8 -*-
from PIL import Image
import numpy as np


def images_to_array(image_files, array_file):
    """  numpy  .npy 
    """
    data = []
    for filename in image_files:
        data.append(np.array(Image.open(filename)))
    np.save(array_file, data)


def load_images(array_file):
    """  .npy 
    """
    return np.load(array_file)


images_to_array(['1.png', '2.png'], '1.npy')
load_images('1.npy')

references

1. https://pillow.readthedocs.io.
2. https://docs.scipy.org/doc/nu.