Picture save as TIFF

excuse me if I make an obvious question.
It is normal that xojo can read .tiff images, but can not save ?


Look into the OSX Command Line utility SIPS (there are topics on this forum about using it to save GIF/TIFF files)

so, i can open tiff image, but for saving,
i have to save the image using another file type (like png) and then convert to tiff with sisp?

I use this ( iw is an imagewell)

  Dim tiffType As New FileType
  tiffType.Name = "TIFF File (*.tiff)"
  tiffType.MacType = "TIFF"
  tiffType.Extensions = "tiff"
  dim file as FolderItem
  dim dlg as new SaveAsDialog
  dlg.Filter = tiffType
  dlg.SuggestedFileName = "export"
  file = dlg.ShowModalWithin(mainwin)
  if file <> nil then
    dim pic as new Picture(iw.Width, iw.Height)
    iw.drawinto(pic.Graphics, 0, 0)
    dim bs as BinaryStream
    bs = BinaryStream.Create(file,true)
  end if