how to set a background image that is in the same folder of the programmung file in css code example

Example 1: CSS adding background image from file

/* The first method using an image on your server */
background: url('img/someimage.jpg');

/* The second method using an image hosted on another server */
background: url('http://www.someimage.com/someimage.jpg');

/* A third method that allows the site to determine protocol instead of explicitly defining it */
background: url('//www.someimage.com/someimage.jpg');

Example 2: background image syntax in css if it in folder

body {
  background: radial-gradient(circle, black, white);
}