Source: George Grantham Bain Collection, Library of Congress, http://www.loc.gov/pictures/item/ggb2006005581/. Photoshopped.
It must be seen that you aren’t a being that smiles.
Gaze is a contemplative gesture. Downward gaze might represent a self remembering what it has felt; upward gaze might represent a self imagining what it is going to feel. In these instances and all others, the represented self is a self looking inward. Nothing outside the self can be thought to matter. That is, in a portrait nothing except the self can be seen to matter.
Technical note about that: in a portrait, selective focus has the effect of subordinating and excluding from consideration all that is not face, contemplating.
Test: as portrayed, does your face entail the term “distinguished”?
The original image:
Henry W. and Albert A. Berg Collection of English and American Literature, The New York Public Library. “Photograph of T. S. Eliot” The New York Public Library Digital Collections. 1940 – 1965. http://digitalcollections.nypl.org/items/669a00aa-c714-2715-e040-e00a180641bb