I think it is because BitBakerr1 didn't explain those pictures when he first posted them in this thread that is the reason it seems there's no difference in those two pictures. Even though BitBakerr1's two pictures look the same, I observed there's a little difference in his two pictures, which I think is difficult to notice, but if you think I am wrong with my observation, you can correct me; there's always room to learn. The first picture of BitBakerr1 shows that BitBakerr1 is pressing downward because of the strength and the stress that is acting on it, while the second picture shows that BitBakerr1 is pressing upward because he is applying little strength and relieving himself from the pain he is undergoing during his push-up.
Even if what you speculatingly describe is true in regards to the pushing down and pushing up, it seems almost irrelevant to show in a picture.. even if some guys might have theories in regards to how they might treat their pushing up different from their pushing down.
Of course, pushing up is harder than pushing down, and most-likely any of us who do our pushups to a point of failure, we will feel our push to fail on the pushing up portion of the pushup rather than on the pushing down portion of the pushup.