Upvote:2
2X2 is the size of the whole thing or paper. For exact measurements of the image itself, see:
https://travel.state.gov/content/passports/en/passports/photos/photos.html
https://travel.state.gov/content/passports/en/passports/photos/photo-composition-template.html
It answers all your questions.
Upvote:5
The exact rules read "Photo should be 2”x2” (51 x 51 mm) with the head centered and sized between 1” and 1.4” (25 and 35 mm)."
This: https://travel.state.gov/content/passports/en/passports/photos/photo-examples.html
Shows multiple examples of OK and not OK photos. I see no examples where a 2x2 photo on a larger media is OK. We personally cut our photos 2 x 2 and have never had an issue (very straight/even with a photo cutter)