procedure SaveBitmapAsWMF(Bitmap: TBitmap; const FileName: string);
var
  Metafile: TMetafile;
  MetafileCanvas: TMetafileCanvas;
begin
  Metafile := TMetafile.Create;
  try
    Metafile.Enhanced := False; // True for EMF
    Metafile.Width  := Bitmap.Width;
    Metafile.Height := Bitmap.Height;

    MetafileCanvas := TMetafileCanvas.Create( Metafile, 0 );
    try
      // Draw the bitmap onto the metafile canvas
      MetafileCanvas.Draw( 0, 0, Bitmap );
    finally
      MetafileCanvas.Free; 
    end;

    Metafile.SaveToFile( FileName );
  finally
    Metafile.Free();
  end;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
  ImageEnView1.IO.LoadFromFile( 'D:\im.jpg' );
  SaveBitmapAsWMF( ImageEnView1.IEBitmap.VclBitmap, 'D:\output.wmf' );
end;