Add image to Author?

Is there a way to add an image (avatar?) for each author? In other words, would like a custom thumbnail image to show next to the Author’s name in each post. Would that be stupid? Is there a way to do this with atahualpa?
See an author’s post *without* an image here: http//www.ProSportTips.com/category/basketball/center/

P.S. I love this theme!!

Thanks.