Element is already the child of another element when adding different images in a UI Element

I am trying to add different page contents in order to pass it to the Print Manager interface. However, when trying to add multiple BitmapImages, it's returning a "Element is already the child of another element." error.

Here's what my current code looks like:

Canvas page = new Canvas
        {
            Width = pageDescription.PageSize.Width,
            Height = pageDescription.PageSize.Height
        };

        Canvas viewablePage = new Canvas()
        {
            Width = pageDescription.ViewablePageSize.Width,
            Height = pageDescription.ViewablePageSize.Height
        };

        viewablePage.SetValue(Canvas.LeftProperty, pageDescription.Margin.Width);
        viewablePage.SetValue(Canvas.TopProperty, pageDescription.Margin.Height);

        // The image "frame" which also acts as a viewport
        Grid photoView = new Grid
        {
            Width = pageDescription.PictureViewSize.Width,
            Height = pageDescription.PictureViewSize.Height
        };

The foreach loop wherein a different image is added to the a different page

foreach(var btm in bitmapImages)
            {
                Image image = new Image
                {
                    Source = btm,
                    HorizontalAlignment = Windows.UI.Xaml.HorizontalAlignment.Center,
                    VerticalAlignment = Windows.UI.Xaml.VerticalAlignment.Center
                };

                // Use the real image size when croping or if the image is smaller then the target area (prevent a scale-up).
                if ((btm.PixelWidth <= pageDescription.PictureViewSize.Width &&
                    btm.PixelHeight <= pageDescription.PictureViewSize.Height))
                {
                    image.Stretch = Stretch.None;
                    image.Width = bitmap.PixelWidth;
                    image.Height = bitmap.PixelHeight;
                }
                photoView.Children.Add(image);
                viewablePage.Children.Add(photoView);
                page.Children.Add(viewablePage);
                pages.Add(page);
            }

bitmapImages is a list of bitmaps. It works if there's only one image to be added but when adding < 1 image to a page, it returns the error. Do you have any suggestions on how should I implement this?

Thanks alot.

Each UI element in UWP can only be used in the UI in one place at one time.
You need to define the UI element every loop.

foreach(var btm in bitmapImages)
{
    Canvas page = new Canvas
    {
        Width = pageDescription.PageSize.Width,
        Height = pageDescription.PageSize.Height
    };

    Canvas viewablePage = new Canvas()
    {
        Width = pageDescription.ViewablePageSize.Width,
        Height = pageDescription.ViewablePageSize.Height
    };

    viewablePage.SetValue(Canvas.LeftProperty, pageDescription.Margin.Width);
    viewablePage.SetValue(Canvas.TopProperty, pageDescription.Margin.Height);

    // The image "frame" which also acts as a viewport
    Grid photoView = new Grid
    {
        Width = pageDescription.PictureViewSize.Width,
        Height = pageDescription.PictureViewSize.Height
    };
    Image image = new Image
    {
        Source = btm,
        HorizontalAlignment = Windows.UI.Xaml.HorizontalAlignment.Center,
        VerticalAlignment = Windows.UI.Xaml.VerticalAlignment.Center
    };

    // Use the real image size when croping or if the image is smaller then the target area (prevent a scale-up).
    if ((btm.PixelWidth <= pageDescription.PictureViewSize.Width &&
        btm.PixelHeight <= pageDescription.PictureViewSize.Height))
    {
        image.Stretch = Stretch.None;
        image.Width = bitmap.PixelWidth;
        image.Height = bitmap.PixelHeight;
    }
    photoView.Children.Add(image);
    viewablePage.Children.Add(photoView);
    page.Children.Add(viewablePage);
    pages.Add(page);
}