The property background-position determines the starting position of a background image, if set. It can take keyword values for horizontal (like 'left', 'center', or 'right') and vertical alignment (like 'top', 'center', or 'bottom') or numerical values (either as a percentage or a length). When specifying, you can give either one or both horizontal and vertical positions. If only one is given, the other defaults to 'center'. If any value isn't a keyword, then the first is the horizontal position and the second (if provided) is for vertical alignment. In essence, background-position combines the roles of background-position-horizontal and background-position-vertical.