Proposed additional chunk for the PNG specification

iCCP Embedded ICC profile

If the iCCP chunk is present, the image samples conform to the color
space represented by the International Color Consortium [ICC]
embedded profile as defined by the ICC and this color space must be
an RGB or monochrome greyscale color space.

The iCCP chunk contains:
    n bytes: profile_name (printable Latin-1 text, 1-79 characters,
             single embedded blanks ok) 
    1 byte:  null separator
    1 byte:  compression_method
             0: zlib datastream using DEFLATE
    n bytes: compressed data stream

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. Applications that are iCCP-aware should
take care that there is only a single profile (explicitly or implicitly)
embedded in a file. Applications that recognize the
iCCP chunk but are not capable of full-fledged color management should
use the gAMA and cHRM chunks.

The profile_name can be any convenient name for referring to the profile;
for example, it could be the same as the ASCII portion of the ICC profile
description tag, minus its trailing null byte.  The rules governing the
contents of the profile_name are the same as those for tEXt keywords.

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

[ICC] International Color Consortium, http://www.color.org