When I load a set of image files into a list and try to display one, it always renders as a gray box.The images are not gray boxes. The size of the image window displayed by openCV varies with the size of the actual image on file.

import cv2
import glob
import random

def loadImages(path):
    
    imdir = path
    ext = ['png', 'jpg', 'gif']    # Add image formats here
    
    files = []
    [files.extend(glob.glob(imdir   '*.'   e)) for e in ext]
    #print("files", files)
    
    images = [cv2.imread(file) for file in files]
    return images

images = loadImages("classPhotos/")
print(str(len(images)), "images loaded")
#print(images)
cv2.imshow("image", random.choice(images))
tmp = input()

CodePudding user response：

Add this 2 lines after cv2.imshow("image", random.choice(images)) to make it work properly.

cv2.waitKey(0) 
cv2.destroyAllWindows() 

• cv2.imshow shows the image instantly and then doesn't show it.
• cv2.waitKey waits for a specific time/ keeps showing the image.
  • putting 0 as an argument makes it wait infinitely unless a key is pressed.
• cv2.destroyAllWindows() helps close the window otherwise it gets stuck.