Configuring MapServer .MAP files to return non-interlaced PNGs

To MetaTile and return PNG (non interlaced) the OUTPUTFORMAT needs to be as follows:

   IMAGETYPE png
   OUTPUTFORMAT
      NAME png
      DRIVER AGG/PNG
      IMAGEMODE RGB
      MIMETYPE "image/png"
      EXTENSION "png"
      FORMATOPTION "INTERLACE=OFF"
   END

Normally the following definition is used for base.map (i.e. overlays)

   MAXSIZE 8192
   IMAGETYPE AGG_Q
 
   OUTPUTFORMAT
      NAME 'AGG_Q'
      DRIVER AGG/PNG
      IMAGEMODE RGBA
      FORMATOPTION "TRANSPARENT=OFF"
      FORMATOPTION "QUANTIZE_NEW=ON"
      FORMATOPTION "QUANTIZE_COLORS=256"
      FORMATOPTION "interlace=off"
   END