These are the two primary profile photos of Hillary Clinton and Donald Trump currently appearing on their respective Wikipedia pages. Of course with any given person having a significant public following, Wikipedia is the first or second most-viewed online source. And although it's primarily an open-source platform, editing of the Wikipedia pages of such higher level biographical pages is limited. There are a fair number of others pictures on each of the 2016 Presidential Candidates' pages - however these two are at the top, and thus by far are the most-viewed pics. Contrasting these two images, which have been almost surely vetted by the candidates - is instructive and insightful nonverbal exercise.
Note here that each image is magnified to the same width for the purpose of this post (with slightly different heights), however the resolution on Donald Trump's original image was significantly lower.
Hillary Clinton's image is posed and taken in a studio whereas Donald Trump's photo was taken at a live event (a town hall meeting at Pinkerton Academy, Derry, New Hampshire in August of 2015).
Secretary Clinton's expression is that of a fairly good "Social Smile" - however it's NOT a sincere smile. The corners of her mouth are pulled primarily upwards (with only the upper teeth visible) - and her cheeks also are (mostly) congruent with this change. Her forehead also displays the necessary requirement of being relaxed. So far so good - so it's a sincere smile?- NO. Look carefully at Hillary's eyes - for they are NOT partially closed - consistent with normal baseline. On the contrary - they are opened slightly (but very significantly) wider than baseline. If one looks at her lower eyelids - there are not the primary and temporary, concave-up furrows present - rather there are several little furrows - some of which are continuous with the "crows feet" at the lateral portion of each eye. This is the reason, when one is assessing a smile, NEVER use the presence of crows feet as a barometer for sincerity (as is sometimes, though erroneously suggested).
TAKE HOME POINT: If Mrs. Clinton had had a dominant, evanescent concave-up furrow on each of her lower eyelids (and the rest of her face was unchanged) - then her smile would have been a sincere smile of joy-happiness (Duchenne Smile) rather than the nice, but very posed, Social Smile.
Donald Trump's expression is certainly not a smile.
His head and torso are tiled away from the person at whom he is looking - and his head is also slightly rotated. We don't look directly at those whom we don't like, don't respect and/or don't believe.
His downward turned mouth corners along with a mild-to-moderate pout (primarily of his lower lip) is, for him, a very common nonverbal mouth display - perhaps his most frequent.
Note also his partially closed eyelids - along with his left eyebrow being raised.
TAKE HOME POINT: This nonverbal cluster present in Mr. Trump's image projects his feelings of doubt/incredulity along with a mild level of dislike and critical evaluation for the person(s) at whom he's looking - and/or their ideas/opinions/proposals, etc., being voiced.
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Nonverbal Communication Analysis No. 3519: Vladimir Putin, The Panama Papers