public synchronized BufferedImage[] getShadeOverlays( int size ) {
		if( shadeOverlays == null || size != shadeOverlaySize ) {
			shadeOverlays = new BufferedImage[16];
			for( int i=0; i<16; ++i ) shadeOverlays[i] = Blackifier.makeShadeOverlay(
				size,
				(i & TileLayerData.SHADE_TL) != 0 ? 1 : 0,
				(i & TileLayerData.SHADE_TR) != 0 ? 1 : 0,
				(i & TileLayerData.SHADE_BL) != 0 ? 1 : 0,
				(i & TileLayerData.SHADE_BR) != 0 ? 1 : 0
			);
			shadeOverlaySize = size;
		}
		return shadeOverlays;
	}