In the first picture you have a ton of slack in your reins and your hands aren't even very far up. To me this says you went into the jump on a long rein. I'd suggest shortening your reins quite a bit so you have a nice bit of contact on the way up to the jump.
For the small jump your release looks about right, I'm assuming you use a slightly longer release over the second, bigger jump. If not, you should be. :)
Second picture on the landing you probably should be sitting like you are at that point. I can't tell from these two pictures whether or not you're sitting down too early, but if you think you are then there are two things you could do to solve that.
First, focus on just holding that release a second or two longer. If you have a steady base of support (and it looks like you're doing okay), then holding the release longer should be no problem, just a matter of getting in the habit.
If, however, the problem is stemming from weakness in your leg, then you'll need to work at tightening that up. With a strong lower leg, you will be able to hold yourself in your 2-point more.
Hope this helped! Good luck!
Every ride, good or bad, teaches you something new.