The Panopticon/Are covers narrative?

Simple really. We know that the story contained in eg. a book, an audio, a graphic novel is the narrative.

But does the cover count as part of the narrative? If something is never stated within the actual story/narrative, but there is something on a cover which seems to indicate it, is that enough to include it as aprt of the narrative? Personally, I don't think it should, as this example illustrates.. [1]

(Perhaps another issue, maybe the same as this...should illustrations for a text story be used as narrative? As an example, in Birth of a Renegade (short story), the illustrations clearly depict the Anthony Ainley incarnation of The Master, despite that being impossible.. [2]

If this needs to be two separate issues, I understand. But can the "final word" be judged based solely on the illustration(s) on the cover?