You seem like a really good, calm, relaxed rider, but it seems like you slump a bit. Try to get your shoulders back and sit up as tall as you can in the saddle. Also it seems like your heels are coming up- try to get them down.
As for the jumping pictures, it seems like you should shorten your stirrups a few holes- it will help you get out of the saddle more. Also get your heels down more and get your feet out of your stirrups more. You are a really good rider though, and your horse is beautiful! I love your plaits.