For elements that have an image, this property sets the area of the image that is used. You can set multiple elements to use the same image but use a different region of the image, reducing the amount of memory required. You can change this property to simulate animation. The syntax is similar to the clip property. All four values are relative to the upper left corner of the image.
* Initial value: content-box * Applies to: all elements * Inherited: no * Percentages: N/A * Computed value: as specified
-moz-image-region: rect(top, right, bottom, left);