I'd say Tony is pretty close.
I used the GS readout from both displays and worked the problem
Pilot ND: 532 Knots GS/207 NM from KADUN/23.5 minutes to KADUN/ KADUN ETA of 0446.3Z = photo time of ~0422.8Z
Co-Pilot ND: 525 Knots GS/214 NM from KADUN/24.3 minutes to KADUN/ KADUN ETA of 0446.5Z =photo time of ~0422.3 Z
Using those figures I'd predict the pictures were taken about 30-40 seconds apart.
However, if you average the ground speeds you get 529 knots... that equates to 8.8 miles/minute....the two pictures are 7 miles apart which equates to 48 seconds
Anyone get anything different, I'm probably missing something.