Hi there 👋 and welcome.
How did you share your pictures ?
If it was, though, quick share :
Settings >connected devices > quick share on "who can share with you" press no one. Also, press on link shared history press on items you want to delete or on picture and press stop sharing on each.
Link sharing: You can disable link sharing in the Samsung Message app or through your phone's settings:
Message app: Open the app, start a new message or select an existing conversation, tap the image icon, and then tap the Link Sharing icon at the bottom.Settings: Go to Settings, then Apps, then Link Sharing, and then Disable.