because senior year you get your own pictures taken and can submit any to yearbook

Well sometimes yes and sometimes no. The only time I received proofs was for my graduation. As for yearbook pictures, every school I've been to (6 of them) would always send students home with a sheet to select what we wanted as a package + background and then we'd bring the sheet back to school along with our parent's money BEFORE taking the pictures.

Where are you from? I only attended three schools in comparison to your six, but here in Canada, we take the pictures before we buy them.

Yea they do this in America

I know at my school seniors took silly pictures for the yearbook because most people got professionally done pictures separately at a studio

For one of my picture day pictures, I wore a "Josie and the Pussycats" leopard print cat ears headband.

seniors get their own pictures taken and yearbook club is run by students.

Not every school does student run yearbooks. The ones at all the schools I went to were school run and they also had rules for what you could wear to them. They also controlled your position and facial expression during them- if you moved or weren't smiling, they'd retake the photo. Which, as someone who does not smile and is actually bad at it, I can confirm that's as much of a pain as it sounds. There were also redo days if the parent wasn't satisfied or you missed the first, but it was an additional fee for redos. It was also before the prints of the official yearbook- they sent home mock-ups either one month after the photos or one month before the yearbook came up. (The latter was for the high school, which had 1200 students one year and 1600 the next, and was waaaaay over capacity. That was when they got done reviewing all the photos, apparently.)

Seconded.