private void addIcon(String path, String filename, String trueFilename, boolean disabledVersion){
        try{
        ImageIcon icon = null;
        
            if(!cache.containsKey(trueFilename)){

                if(disabledVersion){
                    ImageIcon baseicon = new ImageIcon(getClass().getResource(path + filename));
                    Image normalImage = baseicon.getImage();

                    Image grayImage = GrayFilter.createDisabledImage(normalImage);
                    icon = new ImageIcon(grayImage);
                }
                else{
                    icon = new ImageIcon(getClass().getResource(path + filename));
                }
                cache.put(trueFilename, icon);
            }
        }
        catch(NullPointerException e){
            //Icon filename doesn't exist
        }
    }