What a beautiful horse! You two are an awfully nice looking pair.
I would agree with the posters who said you need to give him more of a release. He isn't able to use his neck at all, which is compromising his ability to jump. The uneven legs aren't a major issue in a green horse, however, that left leg is dangling dangerously low to that jump. I've seen green horse get lazy with their legs and trip and fall over low jumps like that ... just because they weren't paying enough attention. Give him more release (don't necessarily lengthen your reins, just push your hands further forward so you still have the contact Delregan's Way was talking about), get him moving out more and give him a good encouraging squeeze as he takes off.
He seems to enjoy jumping, which is a major plus in any horse, but especially one who is just starting out. Keep up the good work!