Every country has their own specifications for passport photos. While the US measures theirs in inches (2x2), 99% of the rest of the planet measures them in millimeters. Most European passports are 35x45mm, but a Chinese passport photo is 33x48mm, far different than all the others.
To be certain you are sending them the correct size for a Chinese passport photo, contact Newsome's Studio of Photography in Carrollwood, located at 10012 N. Dale Mabry Hwy (Cypress Point Office Park). All photography is by appointment, and guaranteed to pass muster, regardless of which country it's for.