Understanding of the size, resolution, and physical dimensions of web images.

1, we usually say that the page image size 500*270, refers to the 500px*270px (that is, the image length and width of the number of pixels);

2, resolution, refers to the unit length (physical length) on the number of pixels. (The most common resolution for web images is 72 pixels per inch)

3, physical size refers to the physical dimensions of the actual external display of the picture (commonly used units cm or inches)

Three relationships: Picture (pixel) size = Resolution * physical size;

Image size: 200kb, which is the amount of memory the image occupies.

(Note: The pixel is not a unit of length, it is a virtual unit, need the resolution of this bridge, in order to correspond with the actual physical size)

Understanding of the size, resolution, and physical dimensions of web images.