Since other's brought it up, in the photo with you on the bike, your foot is pointed slightly down, but I think that is the general angle with the ground of my foot through out the entire stroke, up, down and around.

Though I have my foot further forward on the pedal than yours. And if when riding your foot is also further forward then maybe saddle is too high.

It might feel funny at first, but putting your foot a little more forward on the pedal will reduce any strain your calf muscles and ankles might be feeling on long rides.