The horse is a saint.
There are a few things going wrong here. Before I get into anything I want to say that the following is not meant to be overly harsh but I have some concerns with this rider jumping at all.
Now for critique!
Photo #1 - What a beautiful expression on the horses face, alert, calm and ready. The rider is lacking lower leg strength and compensating by pinching at the knee. This erodes the support that should be offered by the leg and instead creates a weak point from which balance will be lost when the horse jumps.
Photo #2 - You can really see the effects of the pinching knee in this one, position is not solid over the fence, weight should be in the stirrups and center of gravity is too far up the horses neck for a small jump. Again, beautiful attitude from the horse.
Photo #3 - This is what happens when you try and grip with you knees rather than balancing independantly over your horses back, you lose your position altogether as the forelegs contact the ground. Lower leg has been completely lost. The idea of two point is that your lower leg can absorb the shock of the landing and then you return to the saddle gently after the landing is completed. If your two point is not solid, any slight change in direction, incline, decline or landings will dislodge you. This is what happened here. Unfortunately this horse copped the ultimate double whammy, a slammed back and a slammed mouth. This photo makes me cringe.
Remaining photos - The rider adopts an overly forward postion on the flat and the horse is incredibly heavy on the forehand, particularly in photo #6, his hind legs almost seem to be swimming in the air!
This pair are in need of some real coaching. Position needs to be far far more solid on the flat before obstacles are introduced.
I love love love the horse, he looks like such a sweetheart!
All horses deserve, at least once in their lives, to be loved by a little girl.