The size of photos is usually in inches, 1 inch ≈2.54 cm. X-inch photo means that the long side of the photo is X-inch (1 inch photo is the short side). For example, the length of a 5-inch photo is 2.54× 5 =12.7 cm; The length of the 12 inch photo is 2.54×12 = 30.5cm..

ID cards, physical examination forms, etc. are mostly 22mm×32mm small, the photo size of the second-generation ID card is 26mm×32mm, and the ordinary one-inch photo is 25 mm× 35 mm. The size of China passport/travel permit photo is 48mm×33mm, in which the head width is15mm ~ 22mm and the head length is 28mm ~ 33mm.

Related content explanation:

The length and width of the image size are in pixels, and some are in centimeters. Pixel and resolution pixel are the most basic units of digital image, each pixel is a small point, and points (pixels) of different colors gather together to become a moving photo. Digital cameras often use pixels as the basis for classification.

However, many people think that the number of pixels is the number of photosensitive points on the CCD photosensitive unit. In fact, this statement is not completely correct. At present, many manufacturers can produce digital photos with higher resolution under the CCD photosensitive unit with the same photosensitive point through special technology.

The image resolution is the image size and size that can be selected by the digital camera, and the unit is dpi. Common ones are 640 x 480；; 1024 x 768； 1600 x 1200； 2048 x 1536。 In the two sets of numbers of imaging, the former is the width of the picture and the latter is the height of the picture, and the pixels of the picture are obtained by multiplying them. The length-width ratio is generally 4: 3.