Which size do I need?
35 × 45 mm is the most common size worldwide. It is used for UK and EU passports and Schengen visas, as well as Pakistan, Australia and the Indian passport. The US uses a 2 × 2 inch square for passports and visas, as does the Indian visa. Canada asks for 50 × 70 mm, and Chinese visas use 33 × 48 mm.
Rules change from time to time, and some countries reject photos taken at home, so check the official requirements before you print or upload.
Taking a photo that gets accepted
Stand about a metre from a plain, light wall with even light on your face and no shadows behind you. Look straight at the camera with a neutral expression and your mouth closed. Remove glasses if your country requires it, and keep hair away from your eyes. Ask someone else to take the photo from head height rather than taking a selfie, which distorts the face.
In the frame, the top of the head should be close to the top edge, with the chin around three quarters of the way down. Your face should fill about 70% of the photo's height.
Printing for less
The print sheet is a standard 6 × 4 inch (10 × 15 cm) photo with as many copies as fit. Order it as a normal photo print at a pharmacy, supermarket kiosk or online print service and cut along the light grey lines. It usually costs far less than a photo booth. Make sure the print is set to 100% size, not 'fit to page'.