这里是我使用的代码，它的工作很好，但如何我只设置文件类型为jpg和png和不允许/不显示任何其他图像在画廊

private void ButtonOnClick(object sender, EventArgs eventArgs) {
    Intent = new Intent();
    Intent.SetType("image/*");
    Intent.SetAction(Intent.ActionGetContent);
    StartActivityForResult(Intent.CreateChooser(Intent, "Select Picture"), PickImageId);
}

#endregion

#region Get the Path of Selected Image
private string GetPathToImage(Uri uri) {
    string path = null;
    // The projection contains the columns we want to return in our query.
    string[] projection = new[] { 
            Android.Provider.MediaStore.Images.Media.InterfaceConsts.Data };
    using (ICursor cursor = ManagedQuery(uri, projection, null, null, null)) {
        if (cursor != null) {
            int columnIndex = cursor.GetColumnIndexOrThrow(Android.Provider.MediaStore.Images.Media.InterfaceConsts.Data);
            cursor.MoveToFirst();
            path = cursor.GetString(columnIndex);
        }
    }
    return path;
}
#endregion

protected override void OnActivityResult(int requestCode, Result resultCode, Intent data) {
    // For single image Selection
    if ((requestCode == PickImageId) && (resultCode == Result.Ok) && (data != null)) {
        Uri uri = data.Data;
        _imageView.SetImageURI(uri);
        path = GetPathToImage (uri);
    }
}