Passport Size Photo Dimensions
The passport size photo dimensions required varies among countries. 
The following are the size requirements for a United States passport.
Passport Photo Requirements: US
The photo must measure 2 x 2 inches. The picture must be set against a white background. There must be no blemishes or any dirt whatsoever. The face must be clearly visible. The person must look straight into the camera.
You cannot wear dark or tinted glasses. The only glasses that can be worn are medically prescribed glasses. A medical certificate is necessary. You cannot wear a hat, cap or any other headgear that blocks the hairline. Uniforms should not be worn for the photo unless the clothing is worn everyday.
Other Requirements of US Passport Photos
The passport size photo dimensions also require a space of 1 inch or 1 3/8 inches from the bottom of the chin up to the head.
Other requirements state the picture must be taken within the past six months. The shoulder and chest must be seen in the picture.
There shouldn’t be any shadows in the picture. To help you take better pictures, you can use a tripod. If you will be taking the photos yourself, make sure it is in good lighting. Make sure you print on good paper.
Passport Photo Requirements: UK
Two identical photos must be presented. They must measure 45 mm by 35 mm. The background should be a light grey color. It is also important that the passport photo be set visibly against the background. When passport size photo dimensions are printed, make sure it is on low gloss high quality paper.
The photo must be clear and clean. Blemishes and creases are not acceptable. Other people and objects must not be seen in the photograph. The head size must measure 29 to 34 mm. This figure is from the chin to the top of the head. The back and front of the UK passport must not have any writing on it. In addition, the passport must be clear.
Other Requirements for UK Passports
The face must look into the camera. The expression must be neutral. The teeth must not be visible in the photo. The mouth has to be closed. You are not allowed to grin, grimace or make any expression other than the neutral one.
UK Passport Photo Rules for Children Below 5 Years of Age
The photo must be clear, but the child need not have a neutral expression. Glare and spectacles are allowed. The image size is similar to the ones used for adults. The head can be set at an angle.
The child is also not required to look into the camera. For babies, they do not need to have their eyes open. The regulations for children over six are the same for adults. The only difference is that the head can be between 21 to 34 mm.
The passport size photo dimensions are always subject to reviews. Make sure to get in touch with the proper authorities to make sure your photo will be acceptable.
