public void setBackgroundImageOpacity(final double OPACITY) {
        _backgroundImageOpacity = Helper.clamp(0, 1, OPACITY);
        if (null == _backgroundImage) return;
        fireTileEvent(REDRAW_EVENT);
    }
Returns the lower right region.
Only if the getSkin() != null
@return the lower right region
src/main/java/eu/hansolo/tilesfx/Tile.java