Your passport serves as proof of your identity and nationality when you travel in and out different countries. It includes such identifying information as your full name, birthday, citizenship, and your photo.
These days there are plenty of people who try to fake a passport, though. Because of this, passport offices are being stricter these days regarding the pictures you bring. You have to produce forms of identification including drivers license and government ID as well. This way the passport office can compare your photo you bring in with the government issued photo ID you produce.
Your passport photo should be high quality. It must represent you accurately. You also don’t want there to be any defects or problems with the photo, as these can cause delay in your passport.
To be usable as a passport photo, a picture should conform to common passport photo print standards. It should be 2 inch by 2 inch, color, printed on thin photo paper or stock. The print should be continuous tone and should not be retouched or edited in any way.
The photo also has to present your full head. The center of the head must be within the frame, and the eye height should be between 1 1/8 inches to 1 3/8 inches from the bottom of the photo. The photo background needs to be white or off white. Keep a natural expression, and make sure there are no distracting shadows in the photo.
If any of these elements are missing from the photo you wish to use, it can delay your passport. You will end up with your passport application not going through.
Since it is so complex it is likely a good idea to have a professional photo taken by a photographer. This photographer will know how to take a photo that will easily pass muster and not cause a delay in your application.