From your pics, you really need to keep your leg and foot under you. Think about really stretching your heels down and keeping all your weight in the balls of your feet. If your legs keep swinging back like it has in these pics, if something goes wrong like your horses refuses your chances of you tumbling over and on your head and going to be rather high ;). Having a nice solid seat as you approach jumps, not jumping ahead or too early seem like what you need to practice. Try some ground poles in front of jumps to keep you sitting back and tall and letting your horse jump for you, don't get head, will help you keep your leg under you.
Your eyes are looking ahead which is perfect, keeps your back nice and straight. Looks like a nice release in the first pic but in the second pic, did you make it over ok? Looks like an awkward take off :S