pcxBitsPixel()

         Returns the number of bits per pixel of the PCX

    Syntax:

         pcxBitsPixel ( cFile ) -> nBitsPixel

         cFile : Name of the PCX file

    Description:

         This function returns the number of bits per pixel of the PCX
         file if it exists and has a PCX format. Else returns Nil.

    Return:

         The number of bits per pixel or Nil if the file does not exists
         or does not have PCX format.

    Example:

         ? pcxBitsPixel ( "c:\fast\lib\fast.pcx" )