图片数据清洗中超级常用的一招操作！

from PIL import Image

def make_square(im, , fill_color=(0, 0, 0, 0)):
    x, y = im.size
    size = max(x, y)
    new_im = Image.new('RGB', (size, size), fill_color)
    new_im.paste(im, (int((size - x) / 2), int((size - y) / 2)))
    new_img = new_img.resize((224, 224))
    return new_im
    
test_image = Image.open('test.jpg')
new_image = make_square(test_image)
new_image.show()
new_image.save('result.jpg')