OpenCV 여러장의 이미지를 한장으로 출력하는 방법

import cv2
import numpy as np

imglena = cv2.imread('Resources/lena.png')
print(imglena.shape)
# (512, 512, 3)

imgHor = np.hstack((imglena,imglena))
print(imgHor.shape)
# (512, 1024, 3) 이미지 numpy를 더 붙인 형태입니다.

cv2.imshow('hori', imgHor)
cv2.waitKey(0)

import cv2
import numpy as np

def stackImages(scale,imgArray):
    rows = len(imgArray)
    cols = len(imgArray[0])
    rowsAvailable = isinstance(imgArray[0], list)
    width = imgArray[0][0].shape[1]
    height = imgArray[0][0].shape[0]
    if rowsAvailable:
        for x in range ( 0, rows):
            for y in range(0, cols):
                if imgArray[x][y].shape[:2] == imgArray[0][0].shape [:2]:
                    imgArray[x][y] = cv2.resize(imgArray[x][y], (0, 0), None, scale, scale)
                else:
                    imgArray[x][y] = cv2.resize(imgArray[x][y], (imgArray[0][0].shape[1], imgArray[0][0].shape[0]), None, scale, scale)
                if len(imgArray[x][y].shape) == 2: imgArray[x][y]= cv2.cvtColor( imgArray[x][y], cv2.COLOR_GRAY2BGR)
        imageBlank = np.zeros((height, width, 3), np.uint8)
        hor = [imageBlank]*rows
        hor_con = [imageBlank]*rows
        for x in range(0, rows):
            hor[x] = np.hstack(imgArray[x])
        ver = np.vstack(hor)
    else:
        for x in range(0, rows):
            if imgArray[x].shape[:2] == imgArray[0].shape[:2]:
                imgArray[x] = cv2.resize(imgArray[x], (0, 0), None, scale, scale)
            else:
                imgArray[x] = cv2.resize(imgArray[x], (imgArray[0].shape[1], imgArray[0].shape[0]), None,scale, scale)
            if len(imgArray[x].shape) == 2: imgArray[x] = cv2.cvtColor(imgArray[x], cv2.COLOR_GRAY2BGR)
        hor= np.hstack(imgArray)
        ver = hor
    return ver

img = cv2.imread(Resources/shapes.png)
imgGray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
imglena = cv2.imread('Resources/lena.png')

stackimg = stackImages(0.5,[[img,imgGray],
                            [imglena,imglena]])


cv2.imshow('img', stackimg)

cv2.waitKey(0)