I find that when my stirrups are across the widest part of my foot that my heels relax more and go down.
Personally I would try to give the horse a little bit more rein when jumping.
One thing that I am working on myself is making sure that I do not lean on my hands when I am in 2-point. When I lean on my hands my heels tend to go up. Try just holding the mane further up on the neck, or resting your hands lightly on the side of the neck.
If this is the beginning of your jumping career (less than 10 lessons over jumps) I think that you are doing very well. It can take a LOT of time and practice to learn how to jump. If you have more than 10 lessons over jumps you are still doing pretty well, and you already realize about your heels. Good work!
You are learning to fly without wings.
I think your position actually looks quite good. Your back is nice and flat and your head is up and not looking at your fence. It just looks like you might be jumping a little ahead of your horse. As this is such a small fence there's no need to put much effort in on your part other than staying tall with your upper body and closing your lower leg. Let the horse jump up to you. I would also recommend a longer crest release to give your pony a bit more freedom because it just looks like your arms are a little stiff which will leave you in danger of catching your horse in the mouth over larger fences. To correct your heels you could try putting your stirrups up a hole or two and practice riding in two point. Hope that helps.
Crest release is what Jackie also described, grabbing the mane (or a neck strap, or just resting your hands) higher up the neck. It is called a crest release because of where your hands are positioned, which is what you are doing in the picture but further up his mane. Does that make sense? (Why does this now not even make sense to me?!) It is the first stage of giving your horse his head over a jump. Later, once your position is really secure, you'll learn the automatic release, but don't worry about that at this stage.
I think you look fab too Jocelyn ;) You are right where you should be at this stage. You have a good basic position and the rest will come with practice. If your instructor has gotten you this far, I am sure she'll guide you in filling in the details.
You are riding off the toe with a bit too much weight and tension in the digits which has lifted the heel a bit contracting the calf and bringing the leg back in a small "swing" movement...I have a feeling if the fence were higher...we would see more standing in the stirrup and an open knee angle while the leg slipped back even more
Shortening the stirrup a hole or two would have the knee angle better to work from as well and may help with the slight collapse to the left I see in your alignment....it will also allow for more ankle control which would allow you to have the weight drop through the ankle into the heel easier.
You are tense through the shoulder and chest which has travelled down the arm and into the elbow tensing this hinge as well which then restricts your release.
Instead of trying to keep the back flat and shoulders back by over engaging the muscles along the spine...use the cores..lift the upper core for the shoulder placement and stretch the lower core to keep any rounding out of the lower back...this will keep the shoulders soft enough to reach forward allowing the elbow to open more and follow the feel of the horses mouth over the fence and allow the horses arc to come up to you instead of you standing slightly in the irons and up the neck placing you this tad bit ahead of the motion at this moment over the fence.
For just 10 lessons you are doing very well...keep up the good work.