In the story Frindle, Judy receives a copy of the fifth grade class picture at Lincoln Elementary School.  In the picture, the seven fifth grade teachers are standing at the ends of the rows of children, and the children, as is typical in class pictures, are all neatly dressed and carefully groomed.  Upon closer examination, however, Judy notices that each child is holding up a pen, and that their mouths are puckered oddly.  After a moment of confusion, Judy realizes that instead of saying "cheese," the children are all saying "frindle."

Judy Morgan is a reporter for The Westfield Gazette.  She has learned through a co-worker that

...a bunch of fifth graders (are) making trouble and (are) not obeying teachers anymore, that there (is) something about a secret code word they (are) all using.

As there is not a lot of other news that week, Judy decides to investigate the situation, and upon going to the school and doing a few interviews, discovers that the commotion is being caused by a new word, "frindle," which has been invented by a fifth-grader, Nick Allen.  Intrigued, Judy returns to the newspaper office and begins to write a story about what is happening at Lincoln Elementary, and in the morning, a brown envelope arrives at the office, addressed to her.  In the envelope is the fifth grade class picture, with all the kids holding up pens and saying "frindle."

Judy publishes the picture in the newspaper along with her article, thus contributing to the spread of the word's popularity.  It is never revealed exactly who sent the picture, but on the back, written in "neat cursive," is the statement, "3rd row, 5th from left."  In that spot, of course, is Nick Allen (Chapters 9 and 10).