How do you set a background image in CSS?

Setting a background image in CSS is done using the property background-image. This property specifically indicates that you want to use an image as the background of an HTML element. The correct syntax involves using the url() function, which takes the path to the image as its argument. For example, background-image: url('image.jpg'); directs the browser to retrieve and display 'image.jpg' as the background.

This method allows for additional styling to be applied to the background, such as adjusting the position, size, and repeat behavior of the image using related background properties. The clear separation of the background-image property also enhances readability and maintainability of the code.

The other options fail to use the correct syntax or properties defined in CSS. Using background-color is meant for setting a solid color, while image-background and background with the incorrect syntax do not adhere to CSS standards, resulting in the browser failing to recognize those styles.