Saturday, 28 February 2015

IMAGE FORMATS JPEG

JPEG, which stands for joint photographic Experts Group(the group that developed it), is the other popular format for images on the web. JPEG (pronounced jay – peg) is actually a compression type that other file formats can use. The fil format for which it’s known is also commonly called JPEG.

JPEG was designed for the storage of photographic images, Unlike GIF images, JPEG images can include any number of colors. The style of compression the JPEG uses (the compression algorithm) works especially well for ph autographs, so files compressed using the JPEG algorithm are considerably smaller than those compressed using GIF,JPEG use a lossy compression algorithm, which means that some of the data used in the image is discarded to make the file smaller,.Lossy compression works extremely well for photographic data, but makes JPEG unsuitable for image that contain elements with sharp edges, such as logos, line art ,and type. JPEG files are supported by all major web browsers.

PNG

PNG, pronounced “ping,” was originally designed as a replacement for GIFs. It stands for Portable Network Graphics. Only the oldest browsers don’t support PNG natively. Current browsers all support PNG, and it has some important advantage over GIF (and to a lesser extent over JPEG). Like GIF, it is a not –lossy image format. No information about the image is lost when it is compressed.

It has better support for transparency ;than GIF, and supports Platte-based images (like GIF) as well as tru – color and grayscale images (like JPEG). In other words, you don’t have to worry about color usage with PNG, although limiting color usage will result in seller files. More and More sites are using the PNG format for images ,but due mainly to intertie, GIF and JPEG are still the most use do formats. For more information on PNG, see http://www.libpng,org/pub/png/, 

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