Converting coloured images to black and white images

convert.py

from PIL import Image
import numpy as np

gray_images_train = []

# `train_images` is an array containing the image file paths
for img in train_images:
	img = Image.open(img)
	gray = img.convert('L')
	gray_images_train.append(gray)
	
gray_images_train = np.array(gray_images_train, dtype=np.float32)
np.save('gray_images_train.npy', gray_images_train)