4.2.12. iCCP Embedded ICC profile

         If the iCCP chunk is present, the image samples conform to
         the color space represented by the embedded International
         Color Consortium profile as defined by the ICC [ICC].  The
         color space must be an RGB color space for color images (color
         types 2, 3, and 6), or a monochrome greyscale color space for
         greyscale images (color types 0 and 4).

         The iCCP chunk contains:

            Profile name:       1-79 bytes (character string)
            Null separator:     1 byte
            Compression method: 1 byte
            Compressed profile: n bytes

         The format is like the zTXt chunk.  The profile name can be any
         convenient name for referring to the profile, and is subject
         to the same restrictions as a tEXt keyword (printable Latin-1
         characters and nonconsecutive noninitial nonfinal spaces).
         The only value presently defined for the compression method
         byte is 0, meaning zlib datastream with deflate compression.
         Decompression of the remainder of the chunk yields the ICC
         profile.

         An application that creates the iCCP chunk should also create
         gAMA and cHRM chunks that approximate the ICC profile's
         transfer function, for compatibility with applications that do
         not use the iCCP chunk.

         When the iCCP chunk is present, applications that recognize
         it and are capable of color management [ICC] should ignore
         the gAMA and cHRM chunks and use the iCCP chunk instead, but
         applications incapable of full-fledged color management should
         use the gAMA and cHRM chunks if present.

         A file should contain at most one embedded profile, whether
         explicit like iCCP or implicit like sRGB.

         If the iCCP chunk appears, it must precede the first IDAT
         chunk, and it must also precede the PLTE chunk if present.