I agree. YOur stirrups are too long. Your foot is too far through them, too.
The second photo shows the horse almost at the third beat of the canter, when the leading leg strikes the ground. This is when the horse is in its' most "downhill" angle. YOU, on the other hand, at this point should be leaning back or at least very upright in the saddle, just as you would be if your rode your horse down a hill. This helps your and his balance. When he is in the next beat of the canter , reaching under with his strike off leg, he will be in his most uphill part of the canter, when you can be angled a tiny bit forward, as if you were riding him up a hill. If you are leaning forward too much, your hips will be locked and you will not be able to make there adjustments.
Also, your inside shoulder is dropped and advanced too much. This is somthing that you might not need to pay so much attention to as a beginner, but as you go along, you will need to correct his twist in the body. It makes your spine collapse to the inside, and centrifugal force pull you to the outside.
You look up very nicely and in the last two canter shots, your hand position is pretty darn good.
That horse reminds me very much of the mare I leased 11 years ago. She was a dingbat, but a lot of fun.