Thread: making the color dissapear.

hello, i'm new to this forum, i hope to find some answers
my problem is that i have a .png file, and i read the content to a BufferedImage object, then i move that into a
pixel array, the file is a picture of characters that need to be in the game, the problem is that when i paint them,
i can see their background from the file and not the background of the game, i am looking for help as to how to
make the background transparent. i have looked over the web for solutions, but things just won't work,
i have managed to set the Alpha number of the specific color to zero. but still i see in the game panel the gray
color of java's usual background, here is the code:

 // target - the image, rgba - the color to kill.
  public void cleanImage(BufferedImage target,int r,int g,int b,int a)
  {
	  int col = ((a << 24) | (r << 16) | (g << 8) | b);
	  int trans = ((0 << 24) | (r << 16) | (g << 8) | b);
	  int [] pixels = ((DataBufferInt)target.getRaster().getDataBuffer()).getData();
	  ColorModel cm = target.getColorModel();
	  SampleModel sm = target.getRaster().getSampleModel();
	  for (int i = 0;i<pixels.length;i++)
			if (pixels[i] == col) pixels[i] = trans;//-1118482;
	  DataBuffer db = new DataBufferInt(pixels,target.getHeight()*target.getWidth());
		WritableRaster wr = Raster.createWritableRaster(sm,db,null);
		target = new BufferedImage(cm, wr, false, null);
  }