Here's my take on the photo analysis:
Based on how the buildings are aligned in the photo (the right edge of the distant white building aligning with the left edge of the smaller red barn), I put the camera location at approx:
N 40 03 00.29, W 78 52 28.16
You can paste these coordinates straight from here, into Google Earth to see what I'm saying.
Since the plume is slightly left of center of the distant white house, this puts the base of the plume around this point:
N 40 02 55.43, W 78 54 17.11
Now if you measure from this point to the crater location, I think it's about 750 feet. With a 9 mph wind, that's approximately one minute worth of travel. The plume itself looks like it's dissipating to me, and the one minute old figure seems realistic. So what doesn't match is Val's recollection that she took the picture five seconds after hearing the blast.
The FBI does not say it was five seconds, it's just Val saying that. So what it boils down to is one of these two explanations:
A) The government exploded an ordnance a mile East of the crater site, to give Val (and only Val) a shot of a smoke plume that she could photograph with the new camera that the government knew she had close by and ready, for the purpose of demonstrating the crash, but without ever actually using said photo for any evidentiary or propaganda purposes. Also, they had to somehow keep anyone else in the area from seeing this giant smoke plume a mile East of where it ought to be. Also, the people whose back yard the ordnance was detonated in, had to be silenced.
-- or --
B) Val's recollection of how long it took her to snap this photo is off.
Those two seem to be our choices.