If you go check it out yourself and align the photos with satellite images, and then compare clouds in the foreground to the background, you can see that the picture _AF1_5A_3.png was taken BEFORE _AF1_5A_2.png if the flight was going from North to South (as one would expect it to be).
My conclusion is that we may see two more such picture (1.png and 0.png) and that it is a countdown.
By the way, a flight from North to South would go from right to left in the picture, which is DARK to LIGHT (see the picture is brighter on the left side).
It's pretty cool, huh?