The image depicts a young woman emerging/writhing upwards from a mist covered pool upon which lotuses float. Bubbles also rise and form, floating into the air. Behind the figure in the mists can be made out bare trees and two tower-like structures (one on either side of the card). The woman's arms are raised and she clutches at her flaming red hair. Oddly, her hands seem to be webbed. Her eyes are streaked and from the left corner of her mouth blood appears to trickle.
The image provokes some interesting thoughts:
The knowledge offered by the High Priestess is steeped in mystery (the misty setting). It arises (like her) from the pool of the unconscious. It cannot be rushed lest the 'bubbles' burst before they are fully formed. Only once we have understood this knowledge will we be able to penetrate the mists which obscure the distance and will provide a path that can be travelled between the two towers (which are reminiscent of those found in other Tarot decks where they represent the pillars of Boaz and Jachin, the pillars which stood at the entrance to King Solomon's mystic Temple).
Knowledge does not always come without some form of sacrifice (even if this is only commitment to change/transformation) and it may take its emotional toll upon us (the tearing eyes and the trickle of blood).
The lotuses which grow and bloom upon the surface of the pool may very well be significant because the aroma of the lotus is said to bring both tranquillity and heightened awareness.
The image on this card also provides a possible a link between the High Priestess and the water nymph Lotis daughter of Neptune who was transformed into a lotus plant by the gods to protect her from the unwanted (sexual) attentions of the violent and predatory Priapus. (This mythological connection might also explain the 'throes of transformation' posture and the webbed hands of the priestess).
There are hints here, perhaps of a 'victim' theme entering the deck...and a developing response to the attentions of a predator (which might explain those feral females from Card I and the whole 'vampire' overlay in the images we are provided with for many cards in this deck).