How do the different styles of illustration in The Absolutely True Diary of a Part-Time Indian reveal the nature of Junior’s thoughts?

The text uses three main types of illustration. The smaller sketches, usually a quick joke or a passing thought, reveal Junior’s surface thinking in that they are light, comical, and witty. The sketches in darker ink, with detailed captions, are either of people in Junior’s life, such as his family and favorite teachers, or five-paneled cartoons illustrating important aspects of his life, like his poverty or journeys to school. These represent concepts into which Junior has put more thought and care. The lightly penciled portraits are of people close to Junior, whom he wants to illustrate respectfully, like Rowdy, Gordy, and Penelope. Junior draws cartoons to honor his friends and family, and he takes time with their representation.