The thing that leaps to my eye, as a male, is that she has no bra. It is a highly sexual image, in a pseudo-innocent twenties style, with strong suggestions of the "dumb blonde" stereotype - altogether a curious choice, as you say. The mere fact that the author thought it a tolerable female image to use says all that needs be said, except that a lot of people today are so saturated with that particular notion of "women's" sexuality, so-called, that they would not see the difference unless their attention were called to it.