it's that piece of leather that connects the nose band to the throatlatch that is too short. It is pulling thr throatlatch too far forward, no allowing it to fall along the throat line, and thus pulling the juncture point of the browband with the throatlatch piece too low.
I would say, move the clincher piece (that metal thing that holds the throatlatch with the cheek piece/poll piece, to allow the throat latch to fall more straight downward, and thus raise the browband. However, you cannot do this because the piece that is connecting the throatlatch to the noseband is too short. I'd either lengthen that, to allow more freedom in the throatlatch, or take it off. It is not really necessary in a trail bridle like that.