Recently I sent my friend a beautiful image I took in Yosemite of Vernal Falls. He uploaded to his iPhone and showed it to me about a week later. I know I sent him a full resolution photo, but when he zoomed "all the way in," the image was most definably lacking in sharpness. Many details were not visible on the iPhone, that could be seen in the original file. Is this an isolated incident? Is there an option in iTunes/iPhoto that sizes them down?