supports different
      depths, colormaps, etc., and also has a relatively good and
      widely used binary compression format (CCITT Group 4).
      Decompression of G4 is supported by rasterizers in PS and PDF,
      level 2 and above.  G4 compresses better than PNG for most
      text and line art images, but it does quite poorly for halftones.
      It has good and stable support by Leffler's open source library,
      which is clean and small.  Tiff also supports multipage
      images through a dire