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PNG is Replacing GIF Files for Digital Graphic Storage


By Ziv Haparnas

GIF is one of the oldest file formats used for graphics and digital photos storage. GIF has many technical advantages but it also has one big business disadvantage. GIF uses LZW compression which is tangled with patents and licensing issues. The free creation and usage of GIF files was always in debate.

While GIF is a great format for the storage of graphics the usage of GIF files represents some licensing issues. Specifically GIF uses the LZW compression algorithms that are patented and not free to use. GIF became so popular that practically it is used in many places without any practical licensing issues but regardless of the problem being practical and real it drove some industry groups to get organized in order to find a way to solve it once and for all.

One solution that was suggested and implemented was to create a completely new file format that will simply replace the old GIF. This format was called PNG - Portable Network Graphics - and it was designed to be as efficient as GIF but free for use without any risk of licensing or patents issues. PNG was also designed in the Internet era and as such was designed with Internet and networks usage in mind.

Both GIF and PNG were designed and are mostly used for storing graphics. Some people confuse graphics with digital photos although the two are completely different. Graphics are usually computer generated pictures that are built from some basic geometrical objects such as rectangles, triangles and circles. These objects can be combined in complicated ways, colored, filled, brushed, different textured can be used and more. Digital photos on the other hand are generated by digital cameras and by shooting photos of real objects. Digital photos are not built of discrete objects. There are technical implications to that difference mainly in how compression is implemented. For example it is easier to compress graphics (since it is built of known objects and more homogenous colors) than to compress digital photos (since they include areas of different colors, usually some noise and slight variations in colors in each pixel).

To conclude here are short explanations of what the GIF and the PNG formats are:

GIF - Graphics Interchange Format: An old file format initiated by CompuServe. It uses a lossless LZW compression and is thus more efficient than BMP files. GIF files are very efficient for storing basic graphics (that include lines, circles and other graphical shapes) and also efficient for storing small digital photos but are rarely used to store large digital photos as there are more efficient formats for that purpose. GIF files can also include multiple "frames" and support basic animation.

PNG - Portable Network Graphics: This relatively new format was designed to be used in online applications such as web pages. It uses a lossless compression. The original goal of the PNG format was to replace GIF (due to some licensing complications associated with the GIF format). PNG is commonly used now by online web sites to represent small digital photos or graphics replacing the GIF format.

Ziv Haparnas is a technology veteran and writes about practical technology and science issues. This article can be reprinted and used as long as the resource box including the backlink is included. You can find more information about photo album printing and photography in general on http://www.printrates.com - a site dedicated to photo printing.

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