PNG (Portable Network Graphic) specification supplied
by the W3C (World Wide Web Consortium).

Converted from HTML using GoldED and my fingers ;-)

21 Dec. 1996 (1.1): Just added a line so now the index button
                    point to the index page.




PNG is supposed to become a new standard for pictures
on the Web, it also has several advantages over the GIF
format.


GIF features retained in PNG include:

- Indexed-color images of up to 256 colors.
- Streamability: files can be read and written
  serially, thus allowing the file format to be used as a communications
  protocol for on-the-fly generation and display of images.
- Progressive display: a suitably prepared image file can be
  displayed as it is received over a communications link,
  yielding a low-resolution image very quickly
  followed by gradual improvement of detail.
- Transparency: portions of the image can be marked as transparent,
  creating the effect of a non-rectangular image.
- Ancillary information: textual comments and other data can be
  stored within the image file.
- Complete hardware and platform independence.
- Effective, 100% lossless compression.

Important new features of PNG, not available in GIF, include:

- Truecolor images of up to 48 bits per pixel.
- Grayscale images of up to 16 bits per pixel.
- Full alpha channel (general transparency masks).
- Image gamma information, which supports automatic display of images
  with correct brightness/contrast regardless of the machines used to
  originate and display the image.
- Reliable, straightforward detection of file corruption.
- Faster initial presentation in progressive display mode.

PNG is designed to be:

- Simple and portable: developers should be able to implement PNG
  easily.
- Legally unencumbered: to the best knowledge of the PNG
  authors, no algorithms under legal challenge are used.  (Some
  considerable effort has been spent to verify this.)
- Well compressed: both indexed-color and truecolor images are
  compressed as effectively as in any other widely used lossless format,
  and in most cases more effectively.
- Interchangeable: any standard-conforming PNG decoder must read
  all conforming PNG files.
- Flexible: the format allows for future extensions and
  private add-ons, without compromising interchangeability of basic PNG.
- Robust: the design supports full file integrity checking as well
  as simple, quick detection of common transmission errors.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                79039  222017  35.6% -lh5- 0e97 Dec 23  1996 REC-png.guide
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         1 file    79039  222017  35.6%            Dec 24  1997