The size of the 4-inch photo is: 10*7.6cm.

Inch refers to the diagonal length. 4 inches is approximately equal to 13.2 centimeters, which means that the diagonal length of a 4-inch photo is 13.2 centimeters. "Cun" is the traditional Chinese unit of length, while "Chi" and "Zhang" are in decimal system (10 inches = 1 foot, 10 feet = 1 Zhang). In Korea, they are used to express family relationships. For example, 1 inch represents two generations. The relationship between them is a straight line.

Hong Kong legislation adopts the ancient method of one inch equaling 3.33 centimeters. However, this unit has hardly been used in Hong Kong. Only use "inches" (1 inch = 2.54 centimeters) and "centimeters". For example, 5 inches means the photo is 2.54x5=12.7cm long; 12 inches means the photo is 2.54x12=30.5cm long.

Extended information

Regular size data:

1. One inch, 1*1.5 inches, corresponding to 2.5*3.5 centimeters, which is the size of the ID photo.

2. Two inches, 1.5*2 inches, corresponding to 3.5*5.3 centimeters, which is the size of a standard two-inch photo.

3. One inch larger, 3.3*4.8 cm, which is the size of China’s passport.

4. Five inches is also called 3R, 5*3.5 inches, corresponding to 12.7*8.9 cm, which is a relatively common photo size.

5. Six-inch is also called 4R, 6*4 inches, corresponding to 15.2*10.2 cm, which is a relatively common photo size in the world.

6. Seven inches is also called 5R, 7*5 inches, corresponding to 17.8*12.7 centimeters, which is the corresponding enlarged size of other sizes.

7. Eight inches, 6*8 inches, corresponding to 15.2*20.3 cm, about half the size of A4 printing paper.

8. Small twelve inches, 8*12 inches, corresponding to 20.3*30.5 cm, the size is equivalent to A4 printing paper.

9. Twelve inches, 10*12 inches, corresponding to 25.4*30.5 cm.

Reference: Baidu Encyclopedia—Photo Size