Her face is on the currency of UK. I guess it is somewhat like a small image album for her to sho how she has aged over the years. If she had cared to keep a note everytime a new picture of her is painted on it, she could arrange them in a chronological order and see her face change from what it was in 1952 when she became the queen to what it looks like now. To see how her profile has changed, I guess she can refer to a postage stamp collection.