The size of a five-inch photo is12.7cm * 8.9cm.. 5 inches means 5 inches *3.5 inches, 1 inch =2.54cm. Generally speaking, x inches refers to the length of inches on the long side of the photo. Five-inch photos are more common in all kinds of ID photos.

Extended data:

The size of the photo is in inches, 1 inch =2.54cm, and usually x inch refers to the inch length of the long side of the photo. For example, 5 inches means that the photo length is 2.54x5 =12.7cm; 12 inch means that the photo length is 2.54x12 = 30.5cm..

"A few inches" in the photo refers to the length of inches on the long side of the photo. For example, a 6-inch photo means a 6×4-inch photo. There is also a common method to express the size of a photo in the world, that is, take the integer value of the short side of the photo and add the letter R to express it. For example, a 6-inch photo has a specification of 6×4 inches, that is, 4R.

References:

Baidu encyclopedia-photo size