Below, several illustrations showing Jadis caught in the act of stealing a Silver Apple from the book The Magician’s Nephew. This isn’t a scene that’s popular with artists so it was my fortune to find several.
Casually she plucks and bites. He costume is similar to the Pauline Baynes drawing. Note that this scene wasn’t shown in the book but implied, as she has a “horrid stain” around her mouth from the juice when she confronts Digory at the gate.
As she eats the apple here her hand and face turn white, foreshadowing her transformation into the White Witch. The bloodlike stains at her lower lip hint at some kind of vampirism, too.
A monochrome Jadis who has gained eternal life but become slightly haggard in the process. Now she has pointed teeth and ears like a vampire and the inside of the fruit is as red as blood.
In this scene Jadis has already become the White Witch, by her coloration. She watches as Digory picks an apple as instructed by Aslan; the Autumn hues of the garden — gold and brown — imply something in the freshly-created world is already dying. Perhaps it’s innocence.