I love you. Like figuring out the details while trying to paint a portrait, this film takes it's time trying to figure out how to have two ladies express their feelings for one another.
Can our eyes say "I love you"? Our expression? Where does it start, and when does it end? Can you ever just forget your love for someone? On that last question, I think the answer has always been no. It's a permanent feeling. A satisfying and agonizing feeling. Satisfying in terms of knowing that someone you love, loves you back, forever. Agonizing, because it's not something you can actually keep. We can't physically touch or hold "love". We can touch and hold a loved one, but that's in the moment. Physical love is fleeting, but not the emotion of love. Just like these eighteenth century paintings. They're permanent until destroyed. Physical love is like listening to music. It's there and present while it's happening, but after it's over, it's whatever you remember (usually the best parts). And unless you're constantly listening to concerts and orchestrations in this time period, music is fleeting. But emotional love is like the static portraits of their face. It remembers it’s image, and the details within. The combination of moments in one expression.
We have what we have until it's gone. We can only remember and relive the past in our mind. Living in an impossible time where women couldn't really be together, she had to turn around for the last time, or she might've forgotten.
But then again, one can never forget someone they love. So in the end, though not what we or the character's would have preferred, with a last look, they told each other "I love you".