I'm still not sure what she means about this "sex tape is not real" but "I was less than 18" stuff. As best I can piece it together, she means: (1) the stills you saw do not come from a sex tape, but are just some stand-alone WYSIWYG material; (2) while the source is not a sex tape, the stills are really Leighton, but she was not 18 years old (she thinks).

Whether any of that is true, I don't know, but that's my best guess about what she's trying to say.