Finding all Images in a FlowDocument

Question

Since I am pretty new to WPF FlowDocuments I would like to ask if the code below is correct. It is supposed to return all Images contained in a FlowDocument as List:

Answer 1

LINQ is just freaking magical:

public IEnumerable FindImages(FlowDocument document)
{
    return document.Blocks.SelectMany(FindImages);
}

public IEnumerable FindImages(Block block)
{
    if (block is Table)
    {
        return ((Table)block).RowGroups
            .SelectMany(x => x.Rows)
            .SelectMany(x => x.Cells)
            .SelectMany(x => x.Blocks)
            .SelectMany(FindImages);
    }
    if (block is Paragraph)
    {
        return ((Paragraph) block).Inlines
            .OfType()
            .Where(x => x.Child is Image)
            .Select(x => x.Child as Image);
    }
    if (block is BlockUIContainer)
    {
        Image i = ((BlockUIContainer) block).Child as Image;
        return i == null
                    ? new List()
                    : new List(new[] {i});
    }
    throw new InvalidOperationException("Unknown block type: " + block.GetType());
}