>>>>mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QtGui>
#include <QtCore>

class QLabel;
class QPaintEvent;

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow();
     
    QApplication* q_app;

private slots:

   void go();

private:
    QWidget*  w;
    QLabel*   label;
    QImage    image;

    int temp;
        
protected:
    
    void paintEvent(QPaintEvent*);
};

#endif

>>>> main.cpp

#include <QApplication>
#include "mainwindow.h"

int main(int argc, char *argv[]) 
{
    QApplication app(argc, argv);
    
    MainWindow* mw = new MainWindow; 
    mw->q_app = &app;
    
    MainWindow window;
    window.show();
    return app.exec();
}


>>>> mainwindow.cpp

#include "mainwindow.h"

MainWindow::MainWindow()
{
    w = new QWidget(this);
    setCentralWidget(w);

    QWidget *topFiller = new QWidget;
    topFiller->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

    QWidget *bottomFiller = new QWidget;
    bottomFiller->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    
    createActions();
    createMenus();

    setWindowTitle(tr("Main Window"));
    setMinimumSize(160, 160);
    resize(480, 320);
   
    label = new QLabel(w, 0);
    label->setScaledContents(1);
    
    QPushButton* pb = new QPushButton("&Go", this); 
    connect(pb, SIGNAL(triggered()), this, SLOT(go()));

    temp = 1;
}

void MainWindow::go()
{
  for(;;) //i have a timer here, not FOR, but it doesn't play, it to big thing to write..
  {
    //w->repaint();

     QPaintEvent event(QRect(0, 0, roi.width, roi.height));
     q_app->sendEvent(this, &event);
  }
}

void MainWindow::paintEvent(QPaintEvent* event)
{
  if(temp == 1)
  {
    printf("r\n");
    label->setPixmap(QPixmap("/users/my/r.bmp"));
  }    
  else if(temp == 2)
  { 
    printf("s\n");
    label->setPixmap(QPixmap("/users/my/s.bmp"));
    temp = 0;
  }
  
  temp ++;
  
  q_app->processEvents(QEventLoop::AllEvents);
}

picture=new QLabel();
picture2=new QLabel();
pixmap->loadFromData(pointer,lenght,"JPG");
update();

paintEvent(QPaintEvent*)
{
     picture->setPixmap(*pixmap);
     picture2->setPixmap(*pixmap);
}