A passport type photo is any picture that looks like it was professionally taken, with good lighting and sharp focus, and with the person's head and neck filling the photo, at least after it is cropped or trimmed.
The background must be plain, like a screen or plain wall without any visible texture.
The printed photo must be a "portrait" oriented rectangle (vertical screen) of certain dimensions, and the face itself must also be a certain size.
In some circles, it also means a selfie you snap with a 1.8 megapixel phone camera in the bathroom mirror.
As the Commodore said, there are specifications for a passport photo, but less for a 'passport type'. That said, it might be advantageous to tell whoever takes the photo that it's for a school identity not for a passport. I've heard that school ID photos are less expensive.