If you frequently post to your Facebook Story, assuming the photo or video disappears after 24 hours, you might be surprised to learn that a copy of it is saved to your account.
Nobody sees it however, it exists. It is not automatically deleted after the promised 24 hours. All of this happens under the guise of a feature called story archives. If you don't want to keep your Facebook Stories forever, you need to disable Facebook Story Archive.
Facebook Stories archive
Open the Facebook app and you will see the stories at the top. You can scroll through the available stories, but if you look to the top right of the story slider, you'll see an option called "Your archive". Click it. If you've recently posted your story, the Archive of your stories will show your recent posts.
Tap the gear icon at the top right of this screen.
This will take you to the History Archive Settings screen which is just a setting; the option Save to archive. Turn it off and Facebook will no longer save a copy of your story on your account.
Facebook makes it much easier to enable this option than to disable it. Once disabled, the screen offers you a button to activate it from the History Archive screen.
If you remember, a few years ago it was discovered that even after deleting the photos from Facebook, Facebook kept a copy of them. People weren't happy, and Facebook was quick to drop the practice.
The archive is visible only to you. Your friends and followers can't see. In fact, if you wanted to make it available to them, you couldn't. The story itself is not saved unless 24 hours are up. You can use an image or video again or review it, which is the usefulness of the feature. Saved stories don't take up space on your device. The copy is saved online, so if you like the feature, you don't have to worry about taking up too much space on your phone.