(This analysis concerns yesterday's story.)
I set myself a real challenge here, I think, in identifying the chief thermeme. Is it his hand? His ring? Her sheer white garment?
No, I think it's simply the position of her chin, harmonizing with the slightest hint of apprehension in the way her eyelids seem to say that she is trying desperately to keep her eyes fixed downward, to see what will happen next.
It's fascinating to note that the heat here comes entirely from the power-relationship; there's nothing explicit (as that word is usually understood in the context of eroticism) about the photograph. That's why I decided to add one of my very favorite BDSM tropes: what I call "forced anticipation": "Master Frederic" dominates "Maria" simply with words that tell of domination to come. Thus, for us the reader and viewer, the fantasy doubles: not only do we imagine ourselves dominated in the present, but we also must imagine ourselves dominated in the future.