What's "school picture day"? Is it your graduation photo shooting day or something?
"School picture day" is a day in American schools (elementary, middle, and high school) where every student and staff member has their picture taken. These pictures are then given to the children's families to keep and the pictures are also placed in the school yearbook. Many of the students will dress up so they look nice in their pictures, which is why Bubbles was so dressed up. I am unsure if this is done in other countries, but in America, this is done every year in almost every school.