Why does this image have unwanted dot's that disappear when zoomed out?

Question

File format is irrelevant as I changed its format to PNG ,JPEG ,WebP.

Jpeg format of the dotted image:

Answer 1

This is a halftone image, commonly used in newsprint.

The dots are removed by the smoothing algorithm when pixels are merged as the resolution is reduced when zooming out.

Answer 2

Where continuous tone imagery contains an infinite range of colors or greys, the halftone process reduces visual reproductions to an image that is printed with only one color of ink, in dots of differing size (pulse-width modulation) or spacing (frequency modulation). This reproduction relies on a basic optical illusion: the tiny halftone dots are blended into smooth tones by the human eye.

From: https://en.m.wikipedia.org/wiki/Halftone