How does fastbitmap.setGray affects this.bufferedImage

[xyloww]

Hello Sir,
In Catalano.Imaging.Filters, most methods alter
pixelsGray[xstrideX+ystrideY] = (byte) value using FastBitmap.setGray method.
How does pixelsGRAY affects this.bufferedImage in FastBitmap.toIcon/FastBitmap.saveAsJPG?

Also, I am having difficulties displaying images with DataBufferUShort after altering their FBM.pixelsGray[], may I ask if you have any advice to display/save the altered images?

Currently, Ive tried altering FastBitmap.java as follow
private void refresh() {
this.raster = getRaster();

	if (isGrayscale()){
		if (raster.getDataBuffer() instanceof DataBufferByte){
		    pixelsGRAY = ((DataBufferByte) raster.getDataBuffer().getDat
		    a();
		    }
	 else if (raster.getDataBuffer() instanceof DataBufferUShort){
		    pixelData = ((DataBufferUShort) raster.getDataBuffer().getDat
		    a();
		    ByteBuffer byteBuffer = ByteBuffer.allocate(pixelData.length*2);
		    byteBuffer.asShortBuffer().put(ShortBuffer.wrap(pixelData));
		    pixelsGray = byteBuffer.array();
		    
		    }
		}

}

The values in pixelsGray became negative when using invert(), however the this.bufferedImage remains the same.