PNG file
From TrillWiki
PNG stands for Portable Network Graphics. This is a graphics specification brought to us by the World Wide Web Consortium (W3C). (These are the same people who gave the world the XML specification.)
PNG is a full-color image format with lossless compression and alpha-channel transparency.
- Full color
- Unlike a GIF file, which only has 256 colors, PNG supports 24-bit color (16 Million colors)
- Compression
- PNG uses zlib compression. (The same thing that compresses ZIP files.) The file size for the same image is usually smaller than BMP, GIF, and lossless JPEG2000.
- Lossless
- Unlike a JPG file, none of the data is lost when you compress an image using the PNG format.
- Alpha-channel
- Unlike a GIF file, which has 1-bit transparency (on or off), PNG has 8-bit transparency, which means things can have 256 levels of transparency from opaque to transparent. Unfortunately Internet Explorer doesn't support alpha blending natively, so people have had to resort to "flat" images for webpages.
- Non-patented
- Unisys owns the patent to the compression algorithm used in GIF files and was enforcing it. This prompted many to look for an unpatented format and PNG fit the bill.
MNG is the animation wrapper for the PNG format. (Not supported by Trillian.)
[edit] See Also
- PNG support in Trillian
- PNG on FOLDOC
- PNG on Wikipedia
- PNG on Acronym Finder
- W3C's PNG specification
