The orientation of the inserted image is not as expected, example code & file.
Document doc = new Document();
DocumentBuilder builder = new DocumentBuilder(doc);
builder.InsertImage(@"C:\temp\1625269686733.jpg");
doc.Save(@"C:\temp\out.docx", SaveFormat.Docx);
1625269686733.jpg (6.0 KB)
If you insert the same image via word it will be the correct orientation.