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This article mainly introduces what kind of storage format gif format is, with certain reference value, interested friends can refer to, I hope you have a lot of harvest after reading this article, let Xiaobian take you to understand.

The gif format belongs to the "motion picture" storage format. The gif format is a graphics interchange format used to display indexed color images in hypertext markup language;GIF comes in two versions, GIF 87a and GIF 89a, where GIF 89a allows multiple images to be stored in one file, can be animated, and allows certain pixels to be transparent.

The gif format belongs to the "motion picture" storage format.

The full name of GIF is Graphics Interchange Format, which can be translated into Graphics Interchange Format. It is used to display indexed color images in Hypertext Markup Language. It is widely used on the Internet and other online service systems. GIF is a common image file format standard, copyright owned by Compu Serve.

GIF is a bitmap. Bitmaps are basically made up of a number of pixels, each assigned a color, which together make up the picture. GIF uses the Lempel-Zev-Welch (LZW) compression algorithm, which supports up to 256 colors. Because of this property, GIFs are better suited for images with less color, such as cartoon shapes, company logos, and so on. If you encounter situations that require true color, then the expressive power of GIF is limited. GIFs usually come with a palette of colors that you need to use. In Web applications, the size of the image file will obviously affect the download speed, so we can optimize the palette according to the characteristics of GIF palette, reduce the number of colors used in the image (some colors that are not used in the image can be discarded), without affecting the quality of the image.

The biggest difference between the GIF format and other image formats is that it was designed entirely as a common standard and is supported by many platforms due to the popularity of the Compu Serve network. Compu Serve promotes GIFs through free distribution format manuals, but requires software that uses the GIF file format to include a description of its copyright information.

GIF is available in two versions, GIF 87a and GIF 89a.

The GIF 87a version, introduced in 1987, stores one image per file and strictly does not support transparent pixels;GIF 87a uses the LZW compression algorithm, which can compress the image size by 20 to 25 percent while maintaining image quality.

The 89a version of GIF was introduced in 1989, allowing multiple images to be stored in a single file, animated features, and transparency of certain pixels. In this version, GIF documents are expanded with four blocks: graphic control block, comments, description, application programming interface, and support for transparent colors and multiframe animation.

Among them, GIF 89a made significant improvements in transparency, interlaced and animated GIF. The first is support for transparency, GIF 89a allowing parts of an image to be invisible. This property is so important that we can use it in some cases to make the edges of the image no longer appear rectangular, but become arbitrary shapes we want. These transparent areas can be easily generated in Photoshop, Fireworks and exported as GIF images in GIF 89a format. Of course, transparency doesn't mean the border doesn't exist-in fact, it does exist, just doesn't show up, which makes the inserted image more consistent with the overall page.

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