I trying to process a TIFF file using Image class:

using System.Drawing

var i = Image.FromFile("in.tiff");
i.Save("out.tiff");

However, when I do it like this, out.tiff has only the first page of the multipage in.tiff. I know that the information about multiple pages is preserved under Image:

i.GetFrameCount(Imaging.FrameDimension.Page) // Returns 5, which is the number of pages

How can I save i as a full TIFF file instead of a part of it?