How to override original image with edited image in Xamarin forms

public interface IImageEditorDependencyService
{
    Task<Stream> UploadFromGallery(); //Choosing image from gallery for UWP
 
    void UploadFromGallery(MainPage Page); //Choosing image from gallery for Android
 
    void Save(Stream stream); //override the existing image
 
    String GetPath(); //Get the path of selected image from gallery
}

[assembly: Dependency(typeof(ImagePickerImplementation))
public class ImagePickerImplementation : IImageEditorDependencyService
{
    void IImageEditorDependencyService.Save(System.IO.Stream stream)
    {
        Save(stream);
    }
 
    string IImageEditorDependencyService.GetPath()
    {
        return FilePath;
    }
 
    private string GetPathToImage(Android.Net.Uri uri) // Get the path of selected image from gallery
    {
        string imgId = "";
        using (var c1 = activity.ContentResolver.Query(uri, null, null, null, null))
        {
            c1.MoveToFirst();
            string imageId = c1.GetString(0);
            imgId = imageId.Substring(imageId.LastIndexOf(":") + 1);
        }
        string path = null;
        string selection = MediaStore.Images.Media.InterfaceConsts.Id + " =? ";
        using (var cursor = activity.ContentResolver.Query(MediaStore.Images.Media.ExternalContentUri, null, selection, new string[] { imgId }, null))
        {
            if (cursor == null) return path;
            var columnIndex = cursor.GetColumnIndexOrThrow(MediaStore.Images.Media.InterfaceConsts.Data);
            cursor.MoveToFirst();
            path = cursor.GetString(columnIndex);
            FilePath = path;
        }
        return path;
    }
 
    public void Save(System.IO.Stream stream) // Saving the edited image
    {
        stream.Position = 0;
        var fileBytes = ReadFully(stream);
        bytesToBitmap(fileBytes);
        ExportBitmapAsJPG(bytesToBitmap(fileBytes));
    }
 
    void ExportBitmapAsJPG(Bitmap bitmap) // Override the existing image with edited image
    {
        var stream = new System.IO.FileStream(FilePath, System.IO.FileMode.Create);
        bitmap.Compress(Bitmap.CompressFormat.Jpeg, 100, stream);
        stream.Close();
    }
}

[assembly: Dependency(typeof(ImagePickerImplementation))
public class ImagePickerImplementation : IImageEditorDependencyService
{
    public async void Save(Stream stream) // Override the existing image with edited image
    {
        IRandomAccessStream randomAccessStream = stream.AsRandomAccessStream();
        var wbm = new WriteableBitmap(600, 800);
        await wbm.SetSourceAsync(randomAccessStream);
        FolderPicker folderPicker = new FolderPicker();
        folderPicker.FileTypeFilter.Add(".jpg");
        string PathName = Path.GetDirectoryName(FilePath);
        string FileName = Path.GetFileName(FilePath);
        StorageFolder folder = await StorageFolder.GetFolderFromPathAsync(@"" + PathName);
        if (folder != null)
        {
            StorageFile file = await folder.CreateFileAsync(FileName, CreationCollisionOption.ReplaceExisting);
            using (var storageStream = await file.OpenAsync(FileAccessMode.ReadWrite))
            {
                var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, storageStream);
                var pixelStream = wbm.PixelBuffer.AsStream();
                var pixels = new byte[pixelStream.Length];
                await pixelStream.ReadAsync(pixels, 0, pixels.Length);
                encoder.SetPixelData(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Ignore, (uint)wbm.PixelWidth, (uint)wbm.PixelHeight, 200, 200, pixels);
                await encoder.FlushAsync();
            }
        }
    }
 
    public string GetPath() // Get the path of selected image from gallery
    {
        return FilePath;
    }
}

private void Editor_ImageSaving(object sender, ImageSavingEventArgs args)
{
    args.Cancel = true;
    DependencyService.Get<IImageEditorDependencyService>().Save(args.Stream);
    DisplayAlert("Alert", "Image has been Override" + "" + FilePath, "OK");
}