Code included in case someone else has the same problem in the future and is searching for an answer (replace QTextEdit with the widget of your preference):

class TestWindow : public QMainWindow
{
  public:
    TestWindow(QWidget *parent = nullptr) : QMainWindow(parent)
    {
        display = new QTextEdit(this);
        display->setText("Testing");
        display->resize(800, 480);
        display->move(955, 97);
    }

    virtual void paintEvent(QPaintEvent *)
    {
        QPainter painter(this);
        painter.drawImage(0, 0, QImage(":/mockup/panels/Panel.png"));
    }

  private:
    QTextEdit *display;
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    TestWindow testWindow;
    testWindow.show();

    return app.exec();
}

If yes, you can just display the image in a QLabel and then place a widget over that.