I've recently been reading these books and I thoroughly enjoyed them. It conjures a lot of imagery in my mind with the werewolves and the vampires as well as including a North American Red Indian culture.
I also really like the images on the book covers. I like the colour scheme of the red, black and white. I also love the ideas behind them for example, the first book ' Twilight' with the image of the hands offering the red apple which seems to resemble the vampires luring the main human character Bella in, it's similar to the Bible story (where Eve is offered a forbidden apple by the snake in the garden of Eden), or the story of Snow White (with the witch offering Snow White a poisoned apple).
The second book 'New Moon' illustration of the wilted flower looks as though it symbolizes Bella's pain when Edward dumps her.
The third illustration for the book 'Eclipse' shows a torn red ribbon, this could represent how Bella is feeling, that fact that she feels torn between chosing Edward the vampire or Jacob the werewolf. She loves them both but she sees Jacob as more of a friend and yet she doesn't want to lose him.
The fourth illustration for the book 'Breaking Dawn' could perhaps resemble how 'Bella' is closer to becoming a vampire with the idea of the chess pieces on a chessboard. It could also symbolise the Volturi who are a group of leaders for the vampires (you could say the bad guys) and this chess piece could be emphasizing that threat, and how they are after Bella who is symbolised by the red chess piece full of blood.
I like these images as they seem to create an atmosphere. I like the use of photography and the close ups of the elements. I love how simple the images are, using one or two objects to produce a strong and eye catching image.