In my view, neither {I have seen them both}. This is a very famous portrait of the Empress by Levitsky [sic] titled "the lawgiver' reproduced many times and hung in every palace. You can see the law books she is pointing at. The original is in the Kremlin collection, if I recall correctly. The colours of the order she wears is changed, according to which direction the painting was going. Here, she is wearing the ribaund of St Andrew, whereas the most common view is the red of St Catherine. The gowns also changed over the years but the pose [and face]- never. Basically she said " once, and this is it. do with me as you will in time". Sometimes she was, well, portly, at others, almost svelt for 18 century fashion.
I am quite willing to be corrected, if someone can come up with a better answer.