It means, of course, what sight you think might be interesting to have or show or keep an image of.
Photography made image-making accessible to the masses, and thus things like Instagram. The "picturesque" became the "photogenic."
The "photogenic," like aesthetics in general, is socio-culturally defined. We seem to have a few categories for photos: Nature scenes, kids at play, quaint scenes, people who look interesting or attractive, and images used to document moments or things. At this point, a lot of them are cliches (sunsets, waves, babies, old men on benches, etc).
Painting is a Cropsey, Hudson River. We're looking at a photogenic photo image of a picturesque painting of people looking at picturesque scenery.