Second Picture: It looks like your horse is being Mr Pokey!! =) Try to push a full trot out of him and really get him to engage his hind end. When a horse doesn't reach fully into that front hoof print, it makes the rider look like they are over-posting (in that picture it looks a bit to me like an over-post, but I always post more "forward" than "upward".. I feel its a smoother transition on the horses back. It still looks right, i've won championships doing it that way so it can't be too wrong! Lol! :p)
Get him to engage that hiney when he is trotting, and get him into a good frame and you will definitely feel the difference when your trotting!! =) There are a bunch of posts about Engaging the Hind End in the English Riding Forum.. I think =)
I have to say, I am in love with that horse!! I am so fond of high white stockings and very white faces.. just look at Miakoda and Dreamer! LOL! *makes grabby hands*
Looking good. In the first picture I would like your heels down farther, get those hands up and more of a bend in your elbow. Also rolling those shoulders back will help your back look flatter. With that sweater you probably have a beautiful back. I am just pointing out what the jacket might be covering up.