By default, images that your customers upload into your AWS S3 bucket will remain in the bucket forever. After a few months of operation, your bucket could contain many Gb of images and you will incur substantial storage charges from AWS.
AWS offers extensive lifecycle management tools to help you automate the deletion of images after a certain number of days has passed since the original upload. This will help tightly control and minimize the number of images stored in your bucket and thus minimize the monthly storage charges from AWS.