python为图片添加png图片水印

由于工作需要，需要向图片内插入指定密度的水印图，但是发现网上的代码都是向图片里插入文字水印，所以通过插文字水印的思路写了一个插入水印图的程序。

import os
from PIL import Image

#文件夹路径
filePathchoose = 'E:/get_picture/picture'
print(filePathchoose)
#行列数密度
Hang = 2
Lie = 2
#水印参数
shuiyin_path = './2.png'
shuiyin = Image.open(shuiyin_path)
shui_w = int(shuiyin.size[0])
shui_h = int(shuiyin.size[1])

#水印合成
def Picture_Synthesis(M_Img, son_img,shui_w, shui_h, coordinate):
    S_Img = Image.open(son_img).convert('RGBA')
    # # 重新设置子图的尺寸
    icon = S_Img.resize((shui_w, shui_h), Image.ANTIALIAS)
    try:
        # print("已经指定坐标")
        M_Img.paste(icon, coordinate, mask=None)
    except:
        print("坐标指定出错 ")
    # 保存图片
    return M_Img

###程序主干
for root, dirs, files in os.walk(filePathchoose, topdown=True):
    for name in files:
        if '.jpg' in name:
            imagePath = os.path.join(root, name)  # 图片地址
            print(imagePath)
            try:
                img = Image.open(imagePath)  # 读取照片
                image_null = Image.new('RGBA', img.size, (0, 0, 0, 0))
            except:
                continue
            # 打印图片大小
            print(img.size)
            width = int(img.size[0]) # 长度
            height = int(img.size[1])  # 宽度
            #判断是否超限
            if shui_w * Lie > width:
                Hang = int(width // shui_w)
            if shui_h * Lie > height:
                Lie = int(height // shui_h)
            #插入水印图
            if Hang == 1:
                if Lie == 1:
                    x1 = int((width - shui_w) // 2)
                    y1 = int((height - shui_h) // 2)
                    image_null = Picture_Synthesis(image_null, shuiyin_path, shui_w, shui_h, coordinate=(x1, y1))
                else:
                    for j in range(0, Lie):
                        x1 = int((width - shui_w) // 2)
                        y1 = int(j * height // Lie)
                        image_null = Picture_Synthesis(image_null, shuiyin_path, shui_w, shui_h, coordinate=(x1, y1))
            else:
                if Lie == 1:
                    for i in range(0, Hang):
                        x1 = int(i * width // Hang)
                        y1 = int((height - shui_h) // 2)
                        image_null = Picture_Synthesis(image_null, shuiyin_path, shui_w, shui_h, coordinate=(x1, y1))
                else:
                    for i in range(0, Hang):
                        for j in range(0, Lie):
                            x1 = int(i * width // Hang)
                            y1 = int(j * height // Lie)
                            image_null = Picture_Synthesis(image_null, shuiyin_path, shui_w, shui_h, coordinate=(x1, y1))
            try:
                img_PIL = img.convert('RGBA')
                res_image = Image.alpha_composite(img_PIL, image_null)
                res_image = res_image.convert('RGB')
                res_image.save(imagePath)
                print('SUCCESS')
                print("********************")
            except:
                pass