Stephenie said this on her website: twilight: The apple on the cover of Twilight represents "forbidden fruit." I used the scripture from Genesis (located just after the table of contents) because I loved the phrase "the fruit of the knowledge of good and evil." Isn't this exactly what Bella ends up with? A working knowledge of what good is, and what evil is. The nice thing about the apple is it has so many symbolic roots. You've got the apple in Snow White, one bite and you're frozen forever in a state of not-quite-death... Then you have Paris and the golden apple in Greek mythology—look how much trouble that started. Apples are quite the versatile fruit. In the end, I love the beautiful simplicity of the picture. To me it says: choice.
new moon:That is a ruffled tulip. As for the meaning... If you've read the Twilight FAQ, you know that the apple cover had a lot of meaning for me, and I was an active part of the covering process. However, that experience is more the exception than the rule in the publishing world. Something to keep in mind if you intend to embark on a career as a writer: lots of things you might expect to be under your control are not. Covers, for example. Those are mostly up to the publisher and the marketing and sales departments. So I don't know what the tulip means—I didn't have anything to do with this one.
Breaking Dawn's cover is a metaphor for Bella's progression throughout the entire saga. She began as the weakest (at least physically, when compared to vampires and werewolves) player on the board: the pawn. She ended as the strongest: the queen. In the end, it's Bella that brings about the win for the Cullens.
There is no FAQ for the eclipse cover so I think you might be right
that is so right!!!