This property defines the position of a background image. By default the image starting position is set in the top left corder of the window. If the image is set to display on the center and the repeat property is not used, the image will tile starting on the specified position. The values for this property come in pairs the first represent the horizontal and the second the vertical position.
background-position: left top; background-position: 10px 35%;
IE5.5+, FF1+, SA1.3+, OP9.2+
| bottom | Bottom position value. |
| center | Center position value. |
| em | Relative length value. A em unit is equal to the font-size value of the element used. |
| ex | Length value relative to the elements first available font. |
| left | Left side value. |
| Percentage value | The regular format of a percentage value. |
| px | Pixel, a pixel unit represents a single dot on the screen. |
| right | Right position value. |
| top | Top position value. |