imagery on a website. section I. Formats.

For today vivid elements of three formats are useful to check of websites: GIF, JPEG (JPG) plus PNG. To understand, what from the listed formats for what kind schedules approaches, we shall locate out skin of everyone.

1. GIF.

arrangement GIF (Graphics Interchange design ) has been developed during 1987 by corporation CompuServe with initially future for transport of raster images on the complex (local and the Internet). But as the first description of a format has not acceptable hopes - the heading of the image bowed out else volumetric, that for to moment did(ready ) impossible his(its) transport on a Network, two years following , advanced side GIF afterward has gone . Among new-fangled functionalities of a design appeared: sustain of a transparency plus animation, noteworthy reduction of volume of a heading of the image at the cost of support of a LZW-compression.

Algorithm LZW concerns to subsequently -called methods of compression lost-free. With reference near format GIF it earnings , that at use of a means of a LZW-compression here is veto damage or distortions of the numbers of a graphic sleeve . Algorithm LZW is relevant only to 8-bit metaphors .

Format GIF is measured standard for animated metaphors . Process of development of GIF-animation reminds creation of animated film when actions of the character are divided on the workers , niaiy?uea each extra through the certain point interval.

Scopes of a format: diagrams, schedules, the elementary metaphors and aieaoey.

2. JPEG.

system JPEG deciphered as " the incorporated expenses of experts of a photo " (united Photographic Experts Group), is applied to storage of multi-colour photogenic images as provides solidity iieiioaaoiiai images nearly without drop of size (amount) of colors. Process of density occurs on the expenditure of decrease of integer of the pixels containing the information.

During compression present is a converting of the reflection in paint system YCbCr. Channels Cb plus Cr, responsible for shade , decrease during 2 times. subsequently all shade channels of the icon , including black-and-colorless channel Y, segmented (everyone in the size 8o8 pixels). Parts of similes are bare discrete cosinus to makeover - toward algorithm of compression lost-gratis . The ultimate stage: stuffing of the received factors with the help of codes of Haffman.

3. PNG.

PNG (transferable Network Graphics) is a raster format of storage of the striking information lacking loss of quality during compression.

The given plan as alternate GIF reflected. since here and similar opportunities, approximating presence of a transparent background. However because of big, within comparison with GIF, degree of a file through the illustration , and too absence of support of animation, supercilious plans of developers with could not come factual .

Nevertheless, set-up PNG rightly approaches for storage and editing of images by an transitional stage of their making . Graphic editor Macromedia Fireworks for safeguarding of results of processing of the image uses this plan .

GIF, JPEG and PNG. What to desire ?

Format GIF is enhanced for applying to storage of clear elements of a position (the menu, banners, buttons). within format JPEG there should be photos or others iieiioaaoiua imagery . And into PNG opening sketches of a breadboard model of the outlook site can be saved.