I posted below, but just took another look at the senior pictures in my daughter's finished yearbook:
Incredibly, It looks as though about half of all the photos were taken by the student's families themselves, 1/4 used the standard school picture ID issued, and the last 1/4 look to be professionally done, or perhaps by a family member who just knows what they're doing.
I will say it looks as though many families or perhaps students themselves cared more about the pose than the overall image. Some tried for rock-star album cover looks that just aren't formal enough for a yearbook while others took a snapshot from their archives to submit. Not often will you find portrait poses in your family vacation albums.
My daughters' looks fine - my own critique is that I think we cropped in just a little too far to remove a door hinge from the image. I should have taken time to photoshop out the hinge. I also would have liked to see her wear a more formal shirt but she fought me (and won) on using a turquoise knit over a business style blouse. Last note: yes, there are kids in the yearbook wearing T shirts, jeans, sitting or laying oddly and at least one holding a coke bottle... where's that headache icon hiding?