I've divided my web page to left and right container(it's working fine). I made new class in div called "user-cover-container" and it only needs to put cover image on the top left side of the page.
Image is in the same folder as css and HTML file. HTML and css files are merged correctly.
.user-cover-container{
height: 200px;
width: 100px;
background-image: url("bck.jpg");
background-size: cover;
}
<div class=”user-cover-container”> </div>