public void addImage(Integer key, String fileName){
        File imageFile = new File( fileName );
        BufferedImage image;
        Integer pixel;
        List<Integer> pixelList = new ArrayList<Integer>();
        try {
            
            image = ImageIO.read(imageFile);
            for(int i = 0; i < image.getHeight(); i++)
                for(int j = 0; j < image.getWidth(); j++)
                {
                    pixel = image.getRGB(j, i);
                    if(pixel == -1)
                        pixelList.add(-1);
                    else
                        pixelList.add(1);
                }
            
            imageMap.put(key, pixelList);
            printPixelList(pixelList);
            
        } catch (IOException ex) {
            Logger.getLogger(ImageSet.class.getName()).log(Level.SEVERE, null, ex);
        }
    }