I am going to be honest, the picture did make me laugh...
I would go back to grids, and start working on those. I guarantee though, once you get your 2 point down, and you are in correct position, that your horse wont struggle half as much with his strides. But I would NOT be jumping that high if you don't have your position down, and if your legs aren't actually well, being 'used'.
Grid work will be a benefit for you and your horse, as it will help him understand his strides better, and let you start focusing on your position, mostly your legs. Do you have your walk, trot, and canter down perfect on the flat? If so, then you just really need to be working on your position. I find that while your horse is trotting, going into the 2 point, and just staying their while he trots, will help you get the feel for it, and know where the center of gravity is. So while you are trotting around, just go into position. When you are coming up to the fence, about 4 strides before go into position, stay in for about 2 strides, leave position, and then when he jumps, you kind of already know what position is right.
Pretend that you are squatting on the ground, and that the position your in, would you be able to do that on the ground without falling over? Or would you face smash into the ground? Find the center of your gravity. And work on grids! How long is your horses stride?
I would start grid work with about 4-5, one foot high jumps, place all the jumps say, 20-24 feet apart (depending on the horses stride). You need 12 ft for one stride, and 6 ft for landing, and 6 ft for takeoff, so placing them say, 24 feet between leaves the horse one stride, plus takeoff and landing in between. A areil view would look like > ~cantering| 24 | 24 | 24 | 24 | But, if you come in trotting, remember that the first jump that you land, will have less
space needed in between that and the next jump, as he is coming in at a trot, landing a canter, and cantering through the rest. So it would be more like > ~trotting| 20 | 24 | 24 |... and etc.
Once you can do that grid, with your legs working, and your position down, move on to bounces, which are 10-12 feet between (again, depending on horse) ] like > ~trotting| 20 | 24 |12|12|
Then move onto |12|12|12|12|
And etc. Master your position in these grids, and ONLY once you have mastered your position on the lower jumps, then move onto higher jumps.