This document has been reviewed by W3C members and other interested parties and has been endorsed by the Director as a W3C Recommendation. It is a stable document and may be used as reference material or cited as a normative reference from another document. W3C's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment. This enhances the functionality and interoperability of the Web.
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One of the biggest complaints with the Internet is that web pages load too slowly. People don't want to wait while graphics with large file sizes load. To overcome this problem graphics need to be compressed.
Graphics for the web are usually in 72dpi resolution this is a much lower resolution than used in the print industry.
The most common graphic formats supported by web browsers for compressing graphics are JPEG, GIF and PNG.
JPEG - This format is usually used for photos where there are lots of subtle colour changes and detail. The JPEG
Status of this Document
This is a revision of the PNG 1.0 specification, which has been published as RFC-2083 and as a W3C Recommendation. The revision has been released by the PNG Development Group but has not been approved by any standards body.
The PNG specification is on a standards track under the purview of ISO/IEC JTC 1 SC 24 and is expected to be released eventually as ISO/IEC International Standard 15948. It is the intent of the standards bodies to maintain backward compatibility with this specification. Implementors should periodically
Introduction
This document proposes an image format for storing full-color image values in 16-bit pixels. The data representation itself need not be in a PNG (Portable Network Graphics) envelope, but PNG does provide a natural and widely accepted framework for this proposal. PNG is now one of the three image formats supported by the major browsers (Netscape and Internet Explorer), and Microsoft has even declared it to be its primary lossless image format within the Office 98 software suite.
Why 16 bits? Well, 8 bits per pixel is inadequate for
Most of us have heard about PNG by now, but few developers are using it on the Web due to the uneven support within the various Web browsers. The format was developed as a result of the Unisys/GIF controversy and the need to overcome the limitations of both the GIF and JPEG formats. Macromedia has adopted PNG as the native format for its Fireworks product, yet most users are still converting images for the Web to GIF and JPEG.
The next generation of browsers promise more complete support for all the features of this format, but one must wonder if it
SYMPTOMS
If you save an image with a transparent background in Portable Network Graphics (PNG) format and then open the image inside Microsoft Internet Explorer or another Web browser, the image background may appear to be gray rather than transparent.
NOTE: The image background appears to be transparent when you open the image inside Microsoft Picture It! 2000, Microsoft PhotoDraw 2000, or Microsoft Photo Editor.
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CAUSE
This behavior can occur if you enable the True Color option when you save an image in PNG format in PhotoDraw
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