background image url not working

1.container {
2    background-image: url("img/rose.jpg");
3 	height: 800px;
4}
5/* Check Path to image, in this case, its in a folder called img */
6/* Check if you Linked your css File on your header, you Link it in the 
7	Header like this <link rel="stylesheet" href="main.css"> */
8/* Check if the Name of your Image is the same like how you saved it */
9
10

1background-image: url(nickcage.jpg); // No quotes around the file name so just write it down without "nickcage".jpg

1background-image: url(nickcage.jpg); // first problem may be missing quotation mark
2// Second may be wrong path 
3// check the name of the file if there is any error
4// check whether you are using proper extension of the file