Certainly when you are thinking about how the character of Miss Emily changes in this masterful story, one key, intriguing description we are given of Miss Emily and her character is presented to us in the first section towards the end of her life when she is described by the aldermen that go to her home to tell her that she needs to start paying taxes as a drowned corpse. Note the description:
She looked bloated, like a body long submerged in motionless water, and of that pallid hue. Her eyes, lost in the fatty ridges of her face, looked like two small pieces of coal pressed into a lump of dough as they moved from one face to another while the visitors stated their errand.
Note how the similes reinforce the impression of her bloated, dead status - she resembles a corpse that has been "motionless" for some time.
This foreshadows her attachment to the dead Barron that we discover in the final paragraphs of the story - it appears that Miss Emily, in her isolated, withdrawn state, has actually been more "dead" than "alive" for some time - symbolically reflecting the decline of Old Southern values that have departed. She inhabits a lost world which has died long ago.