I have a pic:

Do some conversion:

AB = Image.open("./391.jpg").convert('RGB')
arr=np.array(AB)
gray=arr@np.array([0.2125, 0.7154, 0.0721]) # gray scale now 

Whatever mode you use, it just looks like fucked up:

But if you use scipy.misc.toimage
it is still usable:

I don't know how. Just very strange