It turns out Wikipedians have had a very detailed discussion on the topic. Their current selection on the article for “Human” is of a southeast Asian man and woman, both farmers, who are not wealthy but not destitute, either. Given population demographics, that’s probably about right.
But what’s interesting to me is the background—a rolling landscape, partially forested, that’s a mix of pastoral and agricultural uses. Does this image also represent the average human habitat?