transforms.Normalize is applied on torch.Tensors.
Usually you would have something like this:
transform=transforms.Compose([
    transforms.ToPILImage(),
    transforms.Resize(250),
    transforms.ToTensor(),
	transforms.Normalize(
        mean = [0.485, 0.456, 0.406],
        std = [0.229, 0.224, 0.225])
    ]
)

Since ToTensor() scales the Tensor to [0, 1], you should use “normalized” mean and stddev values.