How does Ha Jin use imagery in In the Kindergarten?

Imagery:

There wasn’t even a purslane leaf on the table. Every one of her classmates looked upset. Not knowing what to say, some children were noisily stirring the corn glue with spoons. Shaona wanted to cry, but she controlled herself. She remembered seeing her teacher leave for home with the bulging duffel clasped on the carrier of her bicycle. At that moment Shaona had thought the green bag must have contained laundry or something, because it was so full. Now she understood, their teacher took their harvest home.