Does someone I share an iCloud link with have access to only the photos/movies in that link, or do they have access to all my photos/movies?

Does someone I share an iCloud link with have access to only the photos/movies in that link, or do they have access to all my photos/movies? I have a few pictures and a video in my iCloud account I want to share with a couple of people who have Apple devices. Will they have access to all my photos/movies other data? Thanks very much for any info/advice. Regards, George