The distance to the earth might have been coincidentally the same as the distance to the other satellite. LEO isn't that far up, the one that took the photo was only ~600km AGL.
But then the resolution can't have been that high, or the other satellite would have been as big as the ISS. It must have been a lot closer than earth.
They've got 0.3m on World View 3, more than enough for what was shown in the gif
Edit: you're probably right, actually.. the silver square on the lower section of landsat 8 is ~1.5m high (guessing from the image on wikipedia), so there should only be ~5-6 pixels for it, but there are clearly more.
