It is quite surprising how more "life-like" the image has become over the years. The first two are so generic-looking, they could represent just about any woman. They don't bear any resemblance to HM at all. However, the two most recent are very like. (Maybe too like? HM does really show her age in the last one).
I wonder who decided that a new one is needed. Was at HM's suggestion (feeling that the current image is too dated?)