Answer:
The photographs help me understand that Buster Keaton got the nickname “The Great Stoneface" because his facial expressions in the two photographs remained the same. He wasn't smiling or even looking bright and cheerful. Also, he wasn't looking like one who easily smiled or changed his facial expressions.
Step-by-step explanation:
Buster Keaton is known to be "The Great Stoneface" because of the way he kept his face which looked the same. He seemed like he wasn't the smiling type of person. So, he seemed to have conditioned his facial expression the way it is. Anytime he is seen, he looks the same way.