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(GIF89a) A variant of the GIFimage format, often used on World-Wide Web pages toprovide moving icons and banners.The GIF89a format supports multiple "frames" that give theimpression of motion when displayed in sequence, much like aflip book. The animation may repeat continuously or playonce.Animated GIFs aren't supported by earlier web browsers,however the first frame of the image is still shown.There are many utilities to create animated GIFs from asequence of individual GIF files. There are also utilitiesthat will produce animated GIFs automatically from a piece oftext or a single image.One problem with this format is the size of the filesproduced, as they are by definition a sequence of individualimages. Apart from minimising the number of frames, the bestway to decrease file size is to assist the LZW compressionby using blocks of solid colour, avoid dithering, and usefewer colours. If areas of an image don't change from oneframe to another, they don't need to be redrawn so make thearea a transparent block in the second frame.