Is there a preferred size and ratio for images that represent a headshot/mugshot of a person? I have a project where we're taking photos of people, generate thumbnails, store the thumbnails and print them on identification cards. Those cards can be swiped by a computer and the photo pops up in a little notification window.
So is there a preferred or standard photo size / ratio for printing on identification cards (drivers licenses, passports, Costco cards)? Also, is there a preferred or standard size / ratio for headshots of people in web or Windows-based UIs?
An example might be a "Meet the Executive Team" section of a website that has executive headshots.
I know some places will do square headshots (StackExchange @ 128x128px), I would prefer a slightly more vertical headshot, but I'm not too picky either way. If there were any standards in this area, it would be great to know what the recommended Square headshot, vertical, or (if this exists) a horizontal image layout dimensions and ratio is.