将图像的一部分覆盖到另一幅图像上

您可以使用OpenCV做到这一点：

#!/usr/local/bin/python3

import numpy as np
import cv2

# Load base image and overlay
base = cv2.imread("image.jpg",   cv2.IMREAD_UNCHANGED)
over = cv2.imread("overlay.jpg", cv2.IMREAD_UNCHANGED)

# Anywhere the red channel of overlay image exceeds 127, make base image red
# Remember OpenCV uses BGR ordering, not RGB
base[over[...,2]>127] = [0,0,255]

# Save result
cv2.imwrite('result.jpg',base)

如果要混合少量的红色（例如20％），同时保留基础图像的结构，则可以执行以下操作：

#!/usr/local/bin/python3

import numpy as np
import cv2

# Load base image and overlay
base = cv2.imread("image.jpg",   cv2.IMREAD_UNCHANGED)
over = cv2.imread("overlay.jpg", cv2.IMREAD_UNCHANGED)

# Blend 80% of the base layer with 20% red
blended = cv2.addWeighted(base,0.8,(np.zeros_like(base)+[0,0,255]).astype(np.uint8),0.2,0)

# Anywhere the red channel of overlay image exceeds 127, use blended image, elsewhere use base
result = np.where((over[...,2]>127)[...,None], blended, base)

# Save result
cv2.imwrite('result.jpg',result)

顺便说一句，您实际上并不需要任何Python，只需在Terminal中使用ImageMagick进行如下操作：

magick image.jpg \( overlay.jpg -fuzz 30% -transparent blue \) -composite result.png

关键字：Python，图像处理，覆盖，蒙版。