Convert PIL style `image` array to torch style image tensor.

def pil2tensor(image:Union[NPImage,NPArray],dtype:np.dtype)->TensorImage:
    "Convert PIL style `image` array to torch style image tensor."
    a = np.asarray(image)
    if a.ndim==2 : a = np.expand_dims(a,2)
    a = np.transpose(a, (1, 0, 2))
    a = np.transpose(a, (2, 1, 0))
    return torch.from_numpy(a.astype(dtype, copy=False) )