I accidentally unchecked the "Visible" checkbox for a screenshot and it disappeared from the preset page. How to unhide it/make it visible again?

I also want to know it.

Enable "Show Hidden Files" within that specific application's settings, often found under a "View" or "Toggle" menu. If the app does not have a dedicated "unhide" button, refreshing the preset list or looking for a "Show Hidden" toggle in the menu is necessary to bring it back.