原理：

1.截图(整个窗口)

2.获取此元素坐标

element = driver.find_element_by_id("xx")

element.location)

3.获取此元素大小

element = driver.find_element_by_id("xx")

element.size

4.根据元素坐标和元素大小确定此元素四个角坐标

5.依赖pillow，根据四角坐标提取图片并保存

案例源码：

首先pip安装pillow

pip install pillow

截图：

# coding:utf-8from selenium import webdriverfrom PIL import Imagedriver = webdriver.Firefox()driver.get('http://www.baidu.com/')driver.save_screenshot('bdbutton.png')element = driver.find_element_by_id("su")print(element.location)                # 打印元素坐标print(element.size)                    # 打印元素大小left = element.location['x']top = element.location['y']right = element.location['x'] + element.size['width']bottom = element.location['y'] + element.size['height']im = Image.open('bdbutton.png')im = im.crop((left, top, right, bottom))im.save('bdbutton.png')