Your position in the first photo is excellent; hard to come up with even a quibble. The pony isn't ideally tight with his front end, but the photo may have been snapped after the ideal moment, and he's certainly able, athletic and safe.
In the second photo, you're slightly ahead of the motion and have pivoted on your knee, faults that like to go together. You can see that your lower leg has slipped behind the girth, you're farther out of the tack than is correct for the size of the fence and you're very close to the pony's neck. Pony is tidier over this fence - forearm is close to horizontal, knees are even, and he's folded nice and tight below the knee.
I am going to respectfully disagree with the previous posters who criticized your release. I think they're expecting to see a more hunter show ring type crest release, and your release is moving towards an auto release, which is absolutely appropriate for your level of riding and discipline. You are not restricting the pony's head and neck at all and are maintaining a soft contact in the air. Your hand and arm appear relaxing and following.
I will point out that you are a very long waisted, tall rider on a short coupled horse. You're going to need to be very careful with your upper body position so as not to unbalance him.