They haven't replaced the ones of Shami Chakrabarti (no longer our Chancellor as she's now Shadow Attorney General). They haven't replaced the ones of the cat. They only replaced the ones of Cheerleader Gal. OK, so the inspirational quote next to her used to say "2nd for student satisfaction", but they could have changed that without changing her picture too.
Why did they replace the pictures of Cheerleader Gal? She was so happy!