The pretty picture may also have been advert.
We've been rolling out the square adverts (MPUs) across the site instead of horizontal adverts for a little while (they've been on every question for the last month or so I think).
Just a bit of the reasoning behind it:
* The ads are usually better
* The ads are worth more/make more money
* We gain a nice editorial area next to the MPU
Making more money means we can invest more into site development, which means we can, hopefully, improve the site for everyone.
Let me know if you have any further questions.