Project project = new Project("New Project.mpp");

project.RootTask.Children.Add("Task1");
PageInfo pageInfo = project.DefaultView.PageInfo;

using (Image image = Image.FromFile("Image1.png"))
{
    pageInfo.Header.CenteredImage = image;
    pageInfo.Legend.LeftImage = image;
    pageInfo.Legend.LeftText = string.Empty;
    MPPSaveOptions options = new MPPSaveOptions();
    options.WriteViewData = true;
    project.Save("AddImageToPageHeaderFooter_out.mpp", options);
}