They are set at their largest. You can make them a little smaller by sliding the highback forward if you untighten the screws (you can also pull the front out a bit if necessary). Make sure your boot is centered on the binding a bit more. I'm not an expert on how the binding is supposed to fit, but seems like it would be ok then though...
Edit: Hmmm, on the other pic it appears they are set to the smallest, did you change them after the first picture or are the two sides set differently?
i set the highbacks to be parallel to my heelside edge