Resizing an image selected by the user using values taken from a combobox

Question

In the project, I am trying to take an image from the user using a file directory, resize it with the value selected from the combobox, and show the resized version in the application, but only the size of the image is printed. How can I solve this problem? Since I'm new to this language and program, I don't know the basics very well, please help.

header code:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include "qlabel.h"
#include <QMainWindow>

QT_BEGIN_NAMESPACE
namespace Ui {
class MainWindow;
}
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();
    void openImage();
    QLabel *label;

private slots:
    void on_pushButton_clicked();

private:
    Ui::MainWindow *ui;

};
#endif // MAINWINDOW_H

MainWindow code:

#include "mainwindow.h"
#include <QLabel>
#include "qdialog.h"
#include "qpushbutton.h"
#include "ui_mainwindow.h"
#include <QFileDialog>
#include <QComboBox>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    setWindowTitle("Hello Label");
    resize(400,500);

    ui->comboBox->addItem("1", QVariant(1));
    ui->comboBox->addItem("2", QVariant(2));
    ui->comboBox->addItem("3", QVariant(3));
    ui->comboBox->addItem("4", QVariant(4));
    ui->comboBox->addItem("5", QVariant(5));
    ui->comboBox->addItem("6", QVariant(6));
    ui->comboBox->addItem("7", QVariant(7));
    ui->comboBox->addItem("8", QVariant(8));
    ui->comboBox->addItem("9", QVariant(9));
    ui->comboBox->addItem("10", QVariant(10));

    QVariant selectedData = ui->comboBox->itemData(ui->comboBox->currentIndex());
    int selectedValue = selectedData.toInt();

    label->setFixedSize(selectedValue*225,selectedValue*225);
    label->setScaledContents(true);

}


MainWindow::~MainWindow()
{
    delete ui;
}


void MainWindow::openImage()
{
    QString fileName = QFileDialog::getOpenFileName(this, tr("Resim Seç"), "", tr("Resim Dosyaları (*.png *.jpg *.bmp)"));
    if (!fileName.isEmpty()) {

        QPixmap pixmap(fileName);
        ui->label->setPixmap(pixmap.scaled(ui->label->size(), Qt::KeepAspectRatio));
        ui->label->setAlignment(Qt::AlignCenter);

    }
}

void MainWindow::on_pushButton_clicked()
{
    connect(ui->pushButton, &QPushButton::clicked, this, &MainWindow::openImage);
}