HPL Sighted

What was HPL thinking when this shot was taken? Do you think he was pondering how best to write about "unspeakable" horrors from outside of our recognizable existence? Something "from beyond" the normal understanding of humankind? Or was he merely contemplating exactly how long he might have to sit there until he could get up and procure himself a bowl of ice cream? He seems so intensely focused, but on what? Obviously NOT the person taking the photograph.