Erised

Scene from Harry Potter and the Philosopher's Stone by J K Rowling.

The mirror's frame is an extension of Harry's vision: the stag fighting the snake symbolises a great many things: pureness of heart (with which Harry defeats Voldemort the next time we encounter the mirror), the quest for one's heart's desire (in Harry's case a family), and Harry's father's animagus shape, which we don't know anything about at this point in the story, as well as Harry's own patronus shape. The serpent of course is Voldemort, and so the figures are both a sad reminder of why Harry is seeing his parents in the Mirror in the first place, as well as foreshadowing Harry's subsequent battles with the Dark Lord at the end of this book, and of the series. The symbols of hope, faith and charity are also in the base of the mirror - most obviously hope (anchor) because that - or the lack of it - is also important for this scene.