python - 如何对 PIL 图像进行零填充？

Question

我想在图像的所有侧面添加零。我尝试：

from PIL import Image
im = Image.open("/content/drive/My Drive/image31.png")

def pad(im,layers):
    return [[0]*(len(im[0])+2*layers)]*layers    + \
           [[0]*layers+r+[0]*layers for r in im] + \
           [[0]*(len(im[0])+2*layers)]*layers
pad(im,1)

错误是：TypeError: 'PngImageFile' object does not support indexing