And you are sure your are padding your saddle enough? you should be able to sit, with your legs out of the stirrups on the pockets of your jeans level. If your "seat" is tipping at all, that will affect your position.. of everything! Legs included. And you are sure your stirrups are measured from tip of fingers to armpit? (Rough guesstimation) but I was just looking at the photo and those are two things I've noticed. Your legs are almost reaching for the stirrups, it seems.
Could you take a picture from a distance on the flat both with feet in the stirrups and then feet long and hanging relaxed? Then a picture of your saddle before you get on, with padding.