The term “photogenic” is most properly applied to light-emitting creatures or sunlight-caused cancerous growths; it’s a physical and biological descriptor.
The most common use of the term today, though, was reportedly coined back in 1925 when producer Samuel Goldwyn described a tennis star and Austrian noble named Count Ludwig von Salm-Hoogstraeten as the next big thing in Hollywood because he was photogenic.
The term—used in reference to someone who looks good on camera—took off from there.
Research into what makes some people photograph “better” than someone else is sparse, in part because this is such a subjective concept.
Does “better” mean more beautiful? Desirable? Adorable? Impressive? More artsy or better composed or interesting-looking or intelligent-seeming?
Some research in this space has focused on variables that influence the way our faces look in photographs, including the angle from which a photo is taken and the color and complexion of our skin.
Skin-tone varies greatly from person to person, as does the smoothness of one’s skin, but all skin-tones also vary based on the health of the person being photographed; so the theory is that if you eat a less-than-healthful diet, your skin hue (and other skin-related details) may shift in a direction that tends to visually read as less-healthy.
The angle of the camera snapping the photo can also affect how we look, as the proportion of some facial features are associated with cute things (large eyes on babies, for instance), fertility (plump, rosy cheeks), or strength (square jaws)—all of which can be perceived as desirable to someone viewing a photo of a face.
Tilting the camera at different angles can make one’s eyes or jaw seem bigger (in proportion to one’s other features) and adjusting the lighting can shift the hue of one’s skin, in both cases potentially achieving a more generally attractive version of what’s already there.
Cosmetics can achieve the same, as can adjusting one’s background, clothing, props, how close the lens is to one’s face, and so on (all of this is true of other animals, too, and potentially non-living compositions, as well).
The camera one uses to capture photos also helps shape how they turn out, and this has always been true to some degree, but it’s arguably becoming an even larger issue (if you want to think of it that way) as our camera tech becomes increasingly sophisticated and relies ever-more heavily on software for processing, rather than leaving captured photons relatively untouched.
Some studies have focused on why many of us don’t like our own selfies, but often feel the opposite about those taken by friends or strangers (even when those friends or strangers don’t like the selfies of themselves that we find attractive).
The results of one such study from 2014 suggest that we may not like how we, personally, look in photographs because we have a mental image of ourselves that differs from reality.
We see friends and family from the outside all the time and thus have a good sense of how they look in real life.
We only see our own faces reflected back at us, though, so our internalized sense of our features may not line up with how they actually look (as shown to us in our selfies).
That discordance between perception and reality may be why many of us are not fans of our own faces, as shown in photographs; it’s not that our features are bad, they’re just different from what we expected to see.
Other research suggests that because our perception of self is so heavily distorted by expectations, we tend to make better, more accurate-to-reality choices about which photos of strangers are better and more likely to be viewed as appealing than we do for our own photos.
Just as we may be prone to giving better advice to other people (compared to the decisions we make for ourselves), then, we may be more accurate judges of how photos look when they feature other, not-us people.
There’s some evidence that taking more photos—and intentionally, thoughtfully analyzing the results—may help selfie-takers become more proficient over time, as it allows us to intuitively connect different on-camera poses and expressions with outcomes we prefer (and the next level of sophistication and expertise is figuring out which poses will result in photos that are most ideal for their intended use-cases—though many of us favor the left-side of our faces, regardless, for what may be neurological reasons).
Ultimately, it's also worth remembering that aesthetic preferences vary substantially—no single person will be considered visually attractive or unattractive to everyone—and that some researchers think selfies help us communicate far more about ourselves than attractiveness or less-attractiveness.
So even if a photo doesn’t seem perfect by superficial visual metrics, it could be a huge success by others.