What Delete actually does on an iPhone
Deleting a photo doesn't erase it. iPhone moves it to Recently Deleted for 30 days, and it stays in iCloud Photos until then. Fidera says so every time, and has a button that opens Photos so you can clear it out of Recently Deleted.
Hide it saves a clean copy with the secret blacked out of the pixels, then deletes the original. An edit in Photos can be undone with one tap, so Fidera doesn't use one.
Leave it is for the screenshot you meant to save. Fidera won't mention it again, and you can change your mind in Settings.
Found means a person should look. Fixed means you hid it, deleted it, or chose to leave it.