There is one exception to this that I know of: AWS Rekognition will re-use the faces you scan with it for training and "to improve and develop the quality of Amazon Rekognition and other Amazon machine-learning/artificial-intelligence technologies." That's so vague, they can reuse it anywhere Amazon (not just AWS) uses machine learning.

You can opt out though.

First point under Data Privacy: https://aws.amazon.com/rekognition/faqs/