WPF Image enlarge via MouseWheel, selected image center does not shift

//xaml
<Window x:Class="WpfApp123.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp123"
        mc:Ignorable="d" WindowState="Maximized"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <Image x:Name="img" Source="{Binding ImgUrl,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
               MouseWheel="img_MouseWheel"> 
        </Image>
    </Grid>
</Window>


//xaml.cs
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApp123
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window,INotifyPropertyChanged
    {
        #region Properties
        private string imgUrl;
        public string ImgUrl
        {
            get
            {
                return imgUrl;
            }
            set
            {
                imgUrl = value;
                OnPropertyChanged(nameof(ImgUrl));
            }
        }

        private double zoomLevel=1.0;
        public double ZoomLevel
        {
            get
            {
                return zoomLevel;
            }
            set
            {
                zoomLevel = value;
                OnPropertyChanged(nameof(ZoomLevel));
            }
        }

        #endregion
        public MainWindow()
        {
            InitializeComponent();
            this.DataContext = this;
            ImgUrl = @"..\..\Images\cl.jpg";
        }

        public event PropertyChangedEventHandler PropertyChanged;
        private void OnPropertyChanged(string propName)
        {
            var handler = PropertyChanged;
            if(handler!=null)
            {
                handler?.Invoke(this, new PropertyChangedEventArgs(propName));
            }
        }

        private void img_MouseWheel(object sender, MouseWheelEventArgs e)
        {
            img.RenderTransform = null;
            var position = e.MouseDevice.GetPosition(img);
            if (e.Delta>0)
            {
                ZoomLevel *= 1.2;
            }
            else
            {
                ZoomLevel /= 1.2;
            }
            img.RenderTransform = new ScaleTransform(ZoomLevel, ZoomLevel, position.X, position.Y);
        }
    }
}

Amplify/enlarge left eye