CSS Background-Image property allows you to display the image at the background of the HTML element or page body. It accepts the value as the URL location of the online hosted image whether it is located at your domain or any other website. You can set the value using url('image path') as discussed in the tutorial: CSS Background-Image property. By default it will display the image at the background repeating it horizontally and vertically starting from the top left to the bottom right of the browser window.
Try the sample below to learn the functionality of CSS Background-Image property: