He took that picture shortly after filling up - 11 mpg and 249 miles left on the tank would imply 22.63 gallons remaining, so unless the gas tank is 30+gallons, it was probably just the drive home.
And for the entire time I've been driving my car, I've averaged about 45 mpg. My best is ~59 mpg over the course of a 250 mile trip, but I have a hybrid, thus I am cheating. I could push it higher with some of the "tricks" that hyper-milers do, but a lot of it starts sacrificing safety (ridiculously over-inflated tires) or time (driving no faster than 55. F-that, I'm going 75-80 on the interstate and getting there in half the time).