The only general wording comment I have is that there are quite a few “the painting”. Putting the title of the painting or changing the wording in some spots, especially in the beginning of a section.
“Study of the Painting” could be changed to “Art Historical Technique in Portrait of Giovanna Tornabuoni “?
You do a great job diving into this painting without bringing too much in about the artist. I enjoyed the lay out and straightforward writing.