Newbie here, my apologies if the question was asked in other words before.
Here is my transfroms function applied on the whole image of a person
transform = transforms.Compose([
    transforms.Resize((224, 224)),
    transforms.RandomHorizontalFlip(),
    transforms.RandomRotation(20),
    transforms.ToTensor(),
    transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))
    ])

I want to apply the CNN only on the face of the person. I have a function that takes image and returns a cropped subimage of the face. How to use this function in my transforms composer ?