why body background image not working code example

Example 1: background-image url not working

background-image: url(nickcage.jpg); // No quotes around the file name so just write it down without "nickcage".jpg

Example 2: css background image not working

.container {
    background-image: url("img/rose.jpg");
 	height: 800px;
}
/* Check Path to image, in this case, its in a folder called img */
/* Check if you Linked your css File on your header, you Link it in the 
	Header like this <link rel="stylesheet" href="main.css"> */
/* Check if the Name of your Image is the same like how you saved it */