Authors may also use the shorthand background property, which is currently better supported than the background-repeat property. No The background-attachment property determines if a specified background image will scroll with the content or be fixed with regard to the canvas. No The background-position property gives the initial position of a specified background image . This property may only be applied to block-level elements and replaced elements. Percentages and lengths may also be used to assign the position of the background image.
Percentages are relative to the size of the element.
Although lengths are allowed, they are not recommended due to their inherent weakness in dealing with differing display resolutions. When using percentages or lengths, the horizontal position is specified first, followed by the vertical position. A value such as 5px 10px specifies that the upper left corner of the image be placed 5 pixels to the right of and 10 pixels below the upper left corner of the element. Combinations of lengths and percentages are allowed, as are negative positions. However, percentages and lengths cannot be combined with keywords.