Why, you ask, would an artist post a simple, sketch, one scarcely completed? Nay, e'en one clearly not completed?
Well, in the olden days before photography became a point-and-click reflex, the only way to create quick images was to learn to "fast sketch". Called croquis, the sketches became part of formal art training beginning in the mid-quattrocento and was emphasized by Andrea del Verrochio, a successful Florentine artist who taught a number of famous artists including Leonardo Da Vinci. Leonardo was a master at fast sketching and his notebooks are full of them.
The ability is still useful since photographs capture an instance of the subject not necessarily the gesture. For subjects that don't like to sit still - like children and other animals - it is de rigeur.
There is even the story that when Thomas Eakins had been hired by the Union Club to paint a portrait of the then-president and former Union general Rutherford B. Hayes he had to rely on croquis. R. B. didn't want to pose but said Tom could come in on one and make drawings while he went about the job of being president. Tom did what he could but when the pointing was finished no one thought it was any good. Mrs. Hayes, who thought her husband looked liked he'd had an afternoon toddy, hated the picture so much she stuck it in a closet somewhere and it hasn't been seen since. We presume that Tom got paid.