part of my CC on the pic is it is framed really tight, head on shots are usually not real flattering on flat work. Especially with them on the rail and a extremely busy background. I would try to get some pics off the rail, or shooting from the rail to the center of the arena but that arena does not look that possible, also try to get at quarters from the front dead on shots are not real eye catchers unless there making a big stop, or coming down the fence with a cow, coming over a jump.... Also if she was looking up and the horse was collected up and in frame it would make a better shot.