Everything about this is beautiful. The city in the back ground slightly out of focus because of the dusty haze and the clouds. I love the armor and the helmet plume. The guard looks very regal.
if you imagine the armor gone, the head is actually the right size. It's just steel plate armor is so bulky, and they dont bulk the helmet up as much since it would really strain the neck. So it makes sense.
i would have thought, the steel helmet would make the head look bigger... so the proportions would be pretty much back to normal. I once wore such a thing. It has a thick layer of leather so to not harm the skin. For this reason it is quite a bit larger than the actual head size.