show image from std::vector<uint8_t> into QGraphicsView

Question

i want to show jpeg data from my vector to QGraphicsView so thid is my code :

void StatusWindow::onThumbPicsChanged(std::map<std::string, std::vector<uint8_t>> files)
{

  QPixmap p;

  p.loadFromData(QByteArray((char *)(files["c@jpg"].data())),"jpg");
// pointers are valid 
  ui->graphicsViewColor->scene()->addPixmap(p);
}

but nothing display

what's wrong