This photograph, taken by Alfred Stieglitz 15 (or 16 or 17, see the endnote in the article from which it is taken) years after they first met, is not one commonly seen of the artist.  First, she is smiling.  Second, she is younger than the most commonly known photographs of her.  The great statement from the beginning of the article from which this comes is:

O’Keeffe achieved a strong personal presence as well through the proliferation of photographs of her hard-bitten, heroic face, which seemed to evoke the early pioneers.

And it goes on to share some facts of her life, including her relationship with the great photographer, that are worth our time of day.