Upon a closer inspection, that thumb was big even in the source image (see below), but still not as big as I drew it. So I had to draw it again. The tendons in the hand don’t trace back properly on this one, but at least my poor drawing subject is not left with a throbbing thumb from some invisible hammer.
And, hey, guess what? The drawing table I set up in my office is really useful when I actually sit down to use it, rather than squeezing drawings in when I’m out and about.
Drawing every day.
-the Centaur