Can not insert a image into a primary footer

Hi
Thanks for your request. Please try using the following code.

Document doc = new Document(@"Test131\Dong_3_test_Signed.doc");
doc.AcceptAllRevisions();
DocumentBuilder builder = new DocumentBuilder(doc);
// Create collection of footer types
ArrayList footerTypesList = new ArrayList();
footerTypesList.Add(HeaderFooterType.FooterEven);
footerTypesList.Add(HeaderFooterType.FooterFirst);
footerTypesList.Add(HeaderFooterType.FooterPrimary);
Image barCode = CreateBarCodeImage("BIC1#######/BIC2#######/TRADEREF1###########/TRADEREF2###########/2007-10-11/2007-09-12/2007-08-13/USD/452345#######/567###.17##");
for (int sectIndex = 0; sectIndex < doc.Sections.Count; sectIndex++)
{
    builder.MoveToSection(sectIndex);
    // InsertBarcode into the each footer in the document
    foreach (HeaderFooterType footerType in footerTypesList)
    {
        if (builder.Document.Sections[sectIndex].HeadersFooters[footerType] != null || sectIndex == 0)
        {
            //// Get page setup for the current section.
            Aspose.Words.PageSetup pageSetup = builder.CurrentSection.PageSetup;
            builder.MoveToHeaderFooter(footerType);
            if (!builder.Document.Sections[sectIndex].HeadersFooters[footerType].IsLinkedToPrevious)
            {
                // We use table with two cells to make one part of the text on the line (with page numbering)
                // to be aligned left, and the other part of the text (with copyright) to be aligned right.
                Table tab = builder.StartTable();
                // Calculate table width as total page width with left and right marins subtracted.
                double tableWidth = pageSetup.PageWidth - pageSetup.LeftMargin - pageSetup.RightMargin;
                builder.InsertCell();
                // Set first cell to the page width.
                builder.CellFormat.Width = tableWidth;
                builder.CellFormat.VerticalAlignment = CellVerticalAlignment.Bottom;
                builder.RowFormat.Height = ConvertUtil.PixelToPoint(barCode.Height);
                builder.ParagraphFormat.Alignment = ParagraphAlignment.Center;
                Shape barcode = builder.InsertImage(barCode);
                builder.EndRow();
                builder.EndTable();
                HeaderFooter hf = (HeaderFooter)builder.CurrentParagraph.GetAncestor(NodeType.HeaderFooter);
                if (!hf.FirstChild.Equals(tab))
                    hf.InsertBefore(tab, hf.FirstChild);
            }
        }
        else
        {
            builder.Document.Sections[sectIndex].HeadersFooters.LinkToPrevious(footerType, true);
        }
    }
}
doc.Save(@"Test131\out.doc");

Hope this helps.
Best regards.