What is the landmark that you think of when you think of Houston?
What if the pic is symbolic in nature, meant purely to define the target city?
It may be that the plane is symbolic as well, representing "attack".
The last time I was in Texas was three years ago to pick up our new pup in San Antonio. We went around Houston then and the only thing I remember was seeing oli refineries and tank farms as far as the horizon and then some. Pretty fat target, I'd say. Especially since any real good primary explosion could set off a daisy chain effect of secondaries.
It could be symbolic.
I just noticed that Casey on the It's Happening site has mentioned that this is actually an "old" picture that she remembers seeing roughly last summer.