Adding an option would be very, very hard. It would require us to pre-load every image every time a page loaded and inspect it for animation. This would not only double the traffic on our webservers (which are, if you've been following this week, already kind of overloaded at times of heavy use), it would slow down loading a page considerably.

It would also only be a solution for one website. If somebody is sensitive to animation, they're probably sensitive to animation everywhere -- so it's better to give people a solution that will work everywhere, not just on one website.