What's With All the Stiff Author Photos?

Seriously. What's the deal?









I found all of these images over at literaryquotes.com and they seem to have a thing against smiling authors. Guh. I'm so tired of the serious writer and the suffering writer. Writing is joyful and healing on some level or none of us would do it.

Does anyone know any statistics on this?
Do writers sell more books if they smile in their author photo?
It would be a fun study to conduct.