Замена текста на изображение в c#

А вот и ответ:

   var app = new Application();
        try {
            //This code creates a document based on the specified template.
            var doc = app.Documents.Add(
                Path.GetFullPath(@"Docs\foo.dotx"),
                Visible: false);
            doc.Activate();
            //for each keyword you want to replace.
            //************************************************
            var keyword = "angus-young";
            Console.WriteLine("Replacing keyword: {0} ...",keyword);
            var sel = app.Selection;                
            sel.Find.Text = string.Format("[{0}]", keyword);                
            sel.Find.Execute(Replace: WdReplace.wdReplaceNone);
            sel.Range.Select();                
            //This code inserts the image
            var imgPath = Path.GetFullPath(string.Format(@"Img\{0}.jpg", keyword));
            sel.InlineShapes.AddPicture(
                FileName: imgPath,
                LinkToFile: false,
                SaveWithDocument: true);
            //************************************************
            //finally, save the doc.
            doc.SaveAs(Path.GetFullPath(@"Docs\foo.docx"));
            doc.Close();
        }
        catch (Exception ex) {
            Console.WriteLine(ex.Message);
        }
        finally {                
            app.Quit();
            sys.Runtime.InteropServices.Marshal.FinalReleaseComObject(app);                
        }
        Console.WriteLine("Press [Enter] to exit");

Console.ReadLine();