Why mobile design is 640 pixels wide?

Question

HTML

The designer sent a PSD layout for the mobile version of the site with a width of 640 pixels. If you make it 1 to 1, then pictures and text look too big on mobile phones, you have to reduce it by about 2 times. Can someone explain what is the hidden meaning of making layouts in this resolution?

Answer 1

iPhone 5s - the physical screen resolution is 640 pixels wide, the logical 320, because the screen is high density, not 1 to 1.
The designer sent it so that you can cut the pictures in the desired resolution.
Just reduce all sizes by half and that's it.

Answer 2

Answer 3

Let him send layouts, in the width that YOU need. And the graphics (icons, pictures) are sent separately.

Answer 4

Don't forget to request SVG icons from it.