paintComponent () method deleting images in JFrame

I need to generate a map according to a txt file that I get as input. Each font in my txt file corresponds to a terrain type of the map. I've created Image arrays that will store the images I can use for each type of terrain and draw those images in the Jframe. I already checked and the path of the images are correct, but as I call the onPaint () method several times during program execution, the map ends up being erased. I need to draw the map only once, and do that, move an avatar over it. How do I draw the map, leave it mounted and just redraw the avatar as it moves?

Follow my code:

    public class MapaInterface extends JPanel implements ActionListener {

    BuscaHeuristicaGameOfThrones busca = new BuscaHeuristicaGameOfThrones();
    private Image fundo;
    private Image explosao = new ImageIcon("src/res/exp1.png").getImage();
    private Image agua = new ImageIcon("/src/res/agua.png").getImage();
    public static ArrayList<Image> grama = new ArrayList<>();
    public static ArrayList<Image> terra = new ArrayList<>();
    public static Agente daenerys;
    private Timer timer;
    FileReader arquivo = null;
    BufferedReader leitor;
    String linha = "";

    public MapaInterface() {
        try {
            arquivo = new FileReader("mapaInvertido.txt");
            leitor = new BufferedReader(arquivo);
        } catch (FileNotFoundException ex) {
            Logger.getLogger(MapaInterface.class.getName()).log(Level.SEVERE, null, ex);
        }
        ImageIcon referencia = new ImageIcon("src/res/mapaGot2.png");
        fundo = referencia.getImage();
        timer = new Timer(1, this);
        preencheArrayDeImagens();
        timer.start();
        daenerys = new Agente();
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D graficos = (Graphics2D) g;
        Random random = new Random();
        int numAleatorio = random.nextInt(23);
        int x = 0, y = 0;
        String tipo = "";
        graficos.drawImage(new ImageIcon("src/res/terrinha.png").getImage(), x,y, this);
        try {
            linha = leitor.readLine();
            StringTokenizer tokenizer;
            while(linha != null){
                tokenizer = new StringTokenizer(linha, ",");
               while(!tipo.equals("|")){
                    tipo = tokenizer.nextToken();
                    if (tipo.equals("T")) {
                        graficos.drawImage(terra.get(numAleatorio), x, y, null);
                        g.dispose();
                    }
                    if (tipo.equals("G")) {
                        graficos.drawImage(grama.get(numAleatorio), x, y, null);
                    }
                    if (tipo.equals("A")) {
                        graficos.drawImage(agua, x, y, null);
                    }
                    x += 16;
                }
                y+=16;
                linha = leitor.readLine();
            }
        } catch (IOException ex) {
            Logger.getLogger(MapaInterface.class.getName()).log(Level.SEVERE, null, ex);
        }
        graficos.drawImage(daenerys.getImagem(), daenerys.getPosicaoMI().getX(), daenerys.getPosicaoMI().getY(), this);
        if (daenerys.chegouDestino == true) {
            graficos.drawImage(explosao, daenerys.getPosicaoMI().getX(), daenerys.getPosicaoMI().getY(), this);
            daenerys.chegouDestino = false;
        }
        g.dispose();
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (daenerys.destinoMuralha == true) {
            if (daenerys.chegouMuralha == false) {
                daenerys.movimentaAgenteMuralha();
                repaint();
            } else {
            }
        } else {
            daenerys.movimentaAgente();
        }
        repaint();
    }

    public static Agente getDaenerys() {
        return daenerys;
    }

    public static void setDaenerys(Agente daenerys) {
        MapaInterface.daenerys = daenerys;
    }

    public void preencheArrayDeImagens() {
        Image blocoTerra = new ImageIcon("src/res/cogumeloterra.png").getImage();
        terra.add(blocoTerra);
        blocoTerra = new ImageIcon("src/res/fogueira.png").getImage();
        terra.add(blocoTerra);
        blocoTerra = new ImageIcon("src/res/tronco.png").getImage();
        terra.add(blocoTerra);
        blocoTerra = new ImageIcon("src/res/tronco2.png").getImage();
        terra.add(blocoTerra);

        Image blocoGrama = new ImageIcon("src/res/florbranca.png").getImage();
        grama.add(blocoGrama);
        blocoGrama = new ImageIcon("src/res/florvermelha.png").getImage();
        grama.add(blocoGrama);
        blocoGrama = new ImageIcon("src/res/matinho.png").getImage();
        grama.add(blocoGrama);
        blocoGrama = new ImageIcon("/src/res/cogumelovermelho.png").getImage();
        grama.add(blocoGrama);

        for (int i = 0; i < 20; i++) {
            grama.add(new ImageIcon("src/res/graminha.png").getImage());
            terra.add(new ImageIcon("src/res/terrinha.png").getImage());
        }
    }

}

I did some testing and this way it works normally:

graficos.drawImage(terra.get(numAleatorio), 16, y, this);
graficos.drawImage(terra.get(numAleatorio), 32, y, this);
graficos.drawImage(terra.get(numAleatorio), 48, y, this);

I can not do this because the terrain type depends on the letters in txt