I needed a passport photo. Beyond my usual photographic concerns (the fact that photos of me all seem to bear an unfortunate resemblance to me), I was required to ensure my photo’s conformity with State Department standards. They photo must be two inches in each dimension, featuring a correctly-proportioned forward-facing non-tilted expressionless face.
To provide guidance, the Department of State offers pictorial guidance, complete with multiple “incorrect” photos, associated “correct” versions, and suggestions for converting the former into the latter.
Guidance like this:
Because if you discover that your square photo is sideways, the easiest thing to do is to fire up your computer, rotate the photo in your editing software, reprint it, and then handle it carefully lest you accidentally rotate it again.