It;s kind of hard to tell,your pictures are too small.Ill try my best.It almost looks like your feet are slipping in your irons,not out of but into.if that makes sense try to keep the pads of the irons near your toes.
The first jump looks like you got a little left over it.keep your toes in.
The second picture don't lean too much on his neck the jumps don't look that big
Third picture,heals down that should help you with your position a little.
If you can, try to get someone to take pictures of you jumping from the side, and make the pictures larger. I can see some points that need improvement but I am hesitant to critique because of the angle. I would, however, highly recommend against riding in sweatpants and sneakers especially when jumping. From what I can see, I would say you need a more solid lower leg and to keep your toes from slipping in the stirrups, and not to brace with your elbows. I can't really see this clearly but you appear to be jumping out of the tack more than you need to. Make sure you aren't catching him in the mouth on the landing. As for the horse, he looks a little grumpy/ears pinned but he tucks his front legs nicely, but he needs to take the jumps straight down the middle, which is something you can help him with.
Are you seriously jumping in tennis shoes?
From what I can see you aren't two pointing in the first pic at all your sitting on his back. Which will keep him unbalenced.
The second one you look fine except your to much on his neck and are over jumping.
You should be in proper clothes.
A) You need proper riding clothes and boots, it will be so much safer.
B) I can't critique you much because of the angle of the photo but your horse seems to be grumpy and his front end is sloppy. He also doesn't seem to round and arch over the jump.