超简易教程：
https://www.youtube.com/watch?v=pf7OONW7l54

1、首先python安装wand的库

sudo pip3 install Wand
sudo apt-get install libmagickwand-dev

2、转换格式

from wand.image import Image as wi

pdf = wi(filename='./cad.pdf', resolution=300)

pdfImage = pdf.convert("jpeg")

i = 1

for img in pdfImage.sequence: #有多张pdf
    page = wi(image=img)
    page.save(filename=str(i)+".jpg")
    i += 1

"""  
    只有一张pdf，就可以使用下面语句
"""
# img = pdfImage.sequence[0]
# page = wi(image=img)
# page.save(filename="cad.jpg")