That is a floating Picture element anchored inside the “Bookmark1” bookmark.
In other words, see this:
DocumentModel document = DocumentModel.Load("headerExample.docx");
var header = document.Sections[0].HeadersFooters[HeaderFooterType.HeaderDefault];
var paragraph = header.Blocks[0] as Paragraph;
foreach (var inline in paragraph.Inlines)
Console.WriteLine(inline.ElementType);
The result is:
BookmarkStart
Picture
Run
BookmarkEnd
Another way you may notice that this Picture is inside the “Bookmark1” bookmark is to change its layout from floating to inline:
thanks for shedding light on this issue!
Your explanation was helpful in understanding the structure of the document.
When moving the picture’s object anchor, I can replace the bookmark text without losing the image.