1, size: the size of an inch photo is 2.5 by 3.5cm, and the size of a small 2 inch photo is 3.3 by 4.8cm, which are different.

2. Use: the small two-inch certificate is used as usual: various diplomas, resumes, etc. One-inch photos are used to apply for identity cards, passports, driver's licenses, etc. , has different uses.