How big is a 20-megapixel photo?

Pixels can be represented by a number, such as a "0.3 megapixel" digital camera with a rating of 300,000 pixels; It can also be represented by a pair of numbers, such as "640x480 display", which means 640 pixels horizontally and 480 pixels vertically (just like VGA display), so its total number is 640x480 = 307,200 pixels.

The color sampling points of digital images (such as JPG files commonly used in web pages) are also called pixels. Due to the different types of computer monitors, these may not correspond to some areas of screen pixels one by one. In this obviously different area, the points in the image file are closer to the texture elements.

Extended data:

When the picture size is in pixels, we need to specify its fixed resolution in order to convert the picture size into the actual size in reality.

For example, the resolution of the most commonly used pictures in web pages is 72, that is, 7265438 pixels per inch +0 inch equals 2.54 cm, then it can be concluded that each cm equals 28 pixels through conversion; Another example is a picture with the length of 15x 15cm, which is equal to the length of 420*420 pixels.

When photographers take photos in JPEG format, the quality of this "built-in magnification" will be better than that of our computer, because the "built-in magnification" is completed before the pictures are compressed into JPEG format. Photographers who have experience in digital photo processing know that enlarging JPEG images in a computer will make the picture quick, delicate and smooth.

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