The bad news: no pictures today! Both girls were facing down (away from the sonographer), so there was no option of cute face shots. I'm going back in 4 weeks, though, so hopefully we'll get to see them then.
The good news: there were no abnormalities, and they're growing at the same rate - twin A is only 4 grams heavier than twin B! There are minor differences - A has a bigger head, and B has longer arms. Overall, the scan put Alison's mind at rest (for the moment, of course).