plt显示灰度图出现Invalid shape问题

转自：https://blog.youkuaiyun.com/grllery/article/details/102470263

transform = transforms.Compose([
    transforms.Grayscale(num_output_channels=1),
    transforms.ToTensor()
])

img = transform(img) 
print(img.size()) # img(1, 681, 1023)
img = np.transpose(img, (1,2,0)) # img(681, 1023, 1)
plt.imshow(img.squeeze()) # img(681, 1023)
plt.show()