Complete picture format details

Picture format is the format used by computers to store pictures. Common storage formats include bmp, jpg, png, tif, gif, pcx, tga, exif, fpx, svg, psd, cdr, pcd, dxf, ufo, eps, ai, raw, WMF, webp, etc. Basic introduction Chinese name: Picture format Common formats: webp, bmp, jpg, png, tif, gif, etc. Application: Picture naming purpose: distinguish pictures Webp format, BMP format, PCX format, TIF format, GIF format, JPEG format, TGA format , EXIF ??format, FPX format, SVG format, PSD format, CDR format, PCD format, DXF format, UFO format, EPS format, AI format, PNG format, HDRI format, RAW format, storage and advantages, applicability, disadvantages, WMF Format, FLIC format, EMF format, ICO format, application method, production process, Webp format WebP (pronounced "weppy") is an image file format that provides both lossy compression and lossless compression, derived from the image encoding format VP8 . It is a format developed after Google purchased On2 Technologies and is released under BSD licensing terms. wep WebP is a new imaging technology launched by Google. It can effectively compress web page images without affecting image format compatibility and actual definition, thereby speeding up the overall web page download speed. Since 65% of the data currently transmitted on the Internet are images, WebP was developed for the purpose of reducing the amount of data and accelerating network transmission. In order to improve JPEG image compression technology, they used an image compressor based on VP8 encoding (open sourced in May 2010), utilizing predictive coding technology, and also used a very lightweight container based on RIFF. This container only adds 20 bytes to each image, but allows image authors to save the metadata they want to store. Like JPEG, WebP is a lossy compression utilizing predictive coding technology. But Google says the format's main advantage is efficiency. They found that "with the same quality, the volume of WebP format images is 40% smaller than JPEG format images. Currently, Google has released a WebP file decoder (libvpx) and a command line tool (webpconv) for JPEG and other formats Conversion between images and WebP formats, but system support is currently limited to Linux, and the Windows version will be launched later. The WebP team is also developing a WebKit core patch to provide native support for the WebP format in the Google Chrome browser. The fly in the ointment is that the encoding time of WebP format images is "8 times longer than JPEG format images." Analysts believe that although the WebP format has not yet been widely supported by various software and hardware like the JPEG format, Google promotes this format. The advantage lies in the Chrome browser. The market share of this browser has reached more than 10%. BMP format bitmap (foreign language abbreviation: BMP, foreign language full name: B it M a P) BMP is a hardware device. Irrelevant image file format, very widely used. It uses a bit-mapped storage format and does not use any other compression except the image depth. Therefore, the BMP file takes up a lot of space. The image depth of the BMP file is optional. 4bit, 8bit and 24bit. When BMP files store data, the image is scanned from left to right and bottom to top. Because the BMP file format is a standard for exchanging image-related data in the Windows environment. , so all graphics and image software running in the Windows environment support the BMP image format. A typical BMP image file consists of three parts: the bitmap file header data structure, which contains the type of BMP image file, display content and other information; Image information data structure, which contains information such as the width, height, compression method, and defined color of the BMP image. BMP is (Windows bitmap) Windows bitmap can be stored in any color depth (from black and white to 24-bit color). Single raster image. The Windows bitmap file format is compatible with other Microsoft Windows programs. It does not support file compression and is not suitable for Web pages. Overall, the disadvantages of the Windows bitmap file format outweigh its advantages. To ensure the quality of photo images, use PNG, JPEG, TIFF files. BMP files are suitable for wallpapers in Windows. Advantages: BMP supports 1-bit to 24-bit color depths with existing Windows programs (especially older programs. ) is widely compatible. Disadvantages: BMP does not support compression, which can result in very large files.

PCX format Personal Computer Exchange (foreign language abbreviation: PCX, foreign language full name: Personal Computer eX change) The formation of this kind of image file has a development process. The first prototype of PCX appeared in a commercial software package for painting called PC PAINBRUSH launched by ZSOFT. Later, Microsoft transplanted it to the Windows environment and became a sub-function in the Windows system. It was first widely used in Microsoft Windows 3.1. With the popularity and upgrade of Windows, coupled with its powerful image processing capabilities, PCX, together with GIF, TIFF, and BMP image file formats, has been used by more and more graphics and image software tools. supported and received more and more attention from people. PCX is the earliest file format to support color images, and now it can support up to 256 colors. PCX designers had the foresight to introduce the color image file format ahead of time, making it a very popular image file format. PCX image files consist of file headers and actual image data. The file header consists of 128 bytes, describing version information and the horizontal and vertical resolution of the image display device, as well as information such as color palette: in actual image data, it represents the image data type and color type. The data in PCX image files are image data compressed using PCXREL technology. PCX is the image file format for PC Paintbrush. The image depth of PCX can be selected from 1, 4, and 8 bit. Because this file format is older, it does not support true color. PCX files use RLE run-length encoding, and the compressed image data is stored in the file body. Therefore, when writing the collected image data into PCX file format, it must be RLE encoded: and when reading a PCX file, it must first be RLE decoded before further display and processing. Advantages: PCX is the standard format among many Windows-based and MS-DOS-based programs. PCX supports internal compression. Disadvantages: PCX is not supported by Web browsers. The TIF format tag image file format (Chinese abbreviation TIF, foreign language abbreviation TIFF, foreign language full name: T ag I mage F ile Format) was developed by Aldus and Microsoft for desktop publishing systems. A more general image file format. The TIFF format is flexible and changeable, and it defines four different formats: TIFF-B is suitable for binary images: TIFF-G is suitable for black and white grayscale images; TIFF-P is suitable for color images with a palette: TIFF- R is suitable for RGB true color images. TIFF supports multiple encoding methods, including RGB compression, RLE compression, JPEG compression, etc. TIFF is the most complex of the existing image file formats. It is scalable, convenient, and modifiable, and can be provided to image editing programs running in environments such as IBM PC. A TIFF image file consists of three data structures, namely the file header, one or more directories containing mark pointers called IFDs, and the data itself. The first data structure in a TIFF image archive is called the Image File Header or IFH. This structure is the only part with a fixed position in a TIFF file; the IFD image file directory is an information block with a variable length of bytes. The Tag mark is the core part of the TIFF file. It is defined in the image file directory to use All image parameters, each directory entry in the directory contains one parameter of the image. GIF format Graphics Interchange Format (foreign language abbreviation: GIF, foreign language full name: Graphics Interchange Format) is an image file format developed by CompuServe in 1987. The data of the GIF file is a continuous tone lossless compression format based on the LZW algorithm. Its compression rate is generally around 50%, and it does not belong to any application. Almost all related software supports it, and a large number of software in the public domain use GIF image files. The data of GIF image files is compressed and uses variable length compression algorithms. Therefore, the image depth of GIF ranges from 1 bit to 8 bit, that is, GIF supports up to 256 colors of images. Another feature of the GIF format is that it can store multiple color images in one GIF file. If the multiple image data stored in one file are read out one by one and displayed on the screen, it can form the simplest animation. GIF decoding is faster because the GIF image is stored in interlaced lines and can be scanned in four passes when decoding and displaying at the same time. Although the first scan only showed one-eighth of the entire image, and the second scan only showed 1/4, it already showed the overview of the entire image. When displaying GIF images, interlaced images will make you feel that they appear to be displayed faster than other images. This is the advantage of interlaced storage; in addition, GIF does not support the Alpha transparency channel.

JPEG format Joint Photographic Experts Group (Foreign language abbreviation: JPEG Foreign language full name: J oint P hotographic E xpert G roup) JPEG is also the most common image format. roup), the file suffix is ??".jpg" or ".jpeg". It is the most commonly used image file format. It was developed by a software development association. It is a lossy compression format that can compress images to a very small size. Due to the limited storage space, duplicate or unimportant data in the image will be lost, thus easily causing damage to the image data. In particular, using an excessively high compression ratio will significantly reduce the quality of the image restored after final decompression. If you pursue high-quality images, it is not advisable to use an excessively high compression ratio. However, JPEG compression technology is very advanced. It uses lossy compression to remove redundant image data, and can display very rich and vivid images while achieving extremely high compression rates. In other words, it can use the least disk space to obtain Better image quality. Moreover, JPEG is a very flexible format that has the function of adjusting image quality, allows files to be compressed with different compression ratios, and supports multiple compression levels. The compression ratio is usually between 10:1 and 40:1. The compression ratio The larger the compression ratio, the lower the quality; conversely, the smaller the compression ratio, the better the quality. For example, a 1.37Mb BMP bitmap file can be compressed to 20.3KB. Of course, you can also find a balance between image quality and file size. The JPEG format mainly compresses high-frequency information and retains color information well. It is suitable for application on the Internet, can reduce image transmission time, can support 24-bit true color, and is also commonly used for images that require continuous tone. Pictures in JPG format. JPEG format is currently the most popular image format on the Internet. It is a format that can compress files to the smallest format. When saving in JPEG format in Photoshop software, it provides 13 levels of compression, represented by levels 0-12. Among them, level 0 has the highest compression ratio and the worst image quality. Even when saving at level 10 quality with virtually no loss of detail, the compression ratio can reach 5:1. When saving in BMP format, a 4.28MB image file is obtained. When saving in JPG format, the file is only 178KB, with a compression ratio of 24:1. After many comparisons, using level 8 compression is the best ratio for both storage space and image quality. The JPEG format is widely used, especially on the Internet and CD-ROM readers. All kinds of browsers support the image format JPEG because the file size of JPEG format is smaller and the download speed is fast. As an upgraded version of JPEG, JPEG2000 has a compression rate about 30% higher than JPEG, and supports both lossy and lossless compression. An extremely important feature of the JPEG2000 format is that it can achieve progressive transmission, that is, first transmit the outline of the image, and then gradually transmit the data, continuously improving the image quality, allowing the image to be displayed from hazy to clear. In addition, JPEG2000 also supports the so-called "region of interest" feature, which allows you to arbitrarily specify the compression quality of the area of ??interest on the image, and you can also select the specified part to decompress first. JPEG2000 has obvious advantages over JPEG and is backward compatible, so it can replace the traditional JPEG format. JPEG2000 can be applied to traditional JPEG markets, such as scanners, digital cameras, etc., and can also be applied to emerging fields, such as network transmission, wireless communications, etc. Advantages: Photographic or realistic works support advanced compression. File size can be controlled with variable compression ratio. Interlacing is supported (for progressive JPEG files). JPEG has extensive support for the Inter standard. Disadvantages: Lossy compression reduces the quality of the original image data. When you edit and resave a JPEG file, the JPEG is mixed with the original image data and degrades in quality. This decline is cumulative. JPEG is not suitable for simpler images that contain few colors, have large areas of similar colors, or have significant differences in brightness. The TGA format tagged graphics (full name in foreign language: Tagged Graphics) format is an image file format developed by the American company Truevision for its display card. The file extension is ".tga" and has been adopted by the international graphics and image industries. accept. TGA has a relatively simple structure and is a universal format for graphics and image data. It has a great influence in the field of multimedia and is the preferred format for converting computer-generated images to television. The biggest feature of the TGA image format is that it can create irregular-shaped graphics and image files. Generally, graphics and image files are square. If you need round, diamond-shaped or even empty image files, TGA can be used. Come in handy! The TGA format supports compression, using a distortion-free compression algorithm. It is a better image format.

EXIF format is an exchangeable image file format (abbreviated as EXIF ??in foreign languages, full name in foreign languages: EX changeable I image file format). The digital camera image file format promoted by Fujifilm in 1994 is actually the same as the JPEG format. The difference is that except for saving image data , it can also store exposure data and incidental information such as shooting date, aperture, shutter, flash data, and small-size images. FPX format flash photo (abbreviated as FPX in foreign languages, full name in foreign languages: kodak Flash P i FPX is a multi-resolution image format, that is, images are stored in a series of different resolutions. The advantage of this format is that the image quality can be maintained when the image is enlarged. In addition, when modifying the FPX image, Only the modified part will be processed, and the entire image will not be processed together, thereby reducing the burden on the processor and memory, and reducing the image processing time. Its multi-resolution storage method is favored by many people. SVG format Scalable vector graphics (referred to as SVG in foreign languages, full name in foreign languages: S calable Vector Graphics). It is based on XML (a subset of Standard Generalized Markup Language) and was developed by the Global Information Network Consortium. An open standard vector graphics language that can be arbitrarily enlarged for graphic display. The edges are extremely clear. The text remains editable and searchable in the SVG image. There are no font restrictions. The generated file is very small and downloads very quickly. Suitable for designing high-resolution Web graphics pages. PSD format P hoto S hop Document (PSD) This is a special file format for Photoshop image processing software. The file extension is. psd, which can support various image features of layers, channels, masks and different color modes, is a non-compressed original file saving format. The scanner cannot directly generate files in this format. PSD files sometimes have a large capacity, but since all original information can be retained, it is the best choice to save images in PSD format during image processing that have not yet been completed. CDR format CDR format is a dedicated graphics file format for the famous drawing software CorelDRAW. Since CorelDRAW is a vector graphics drawing software, CDR can record the attributes, location, paging, etc. of the file. However, it has poor compatibility. It can be used in all CorelDraw applications, but other image editing software cannot open such files. PCD format photo CD (foreign language abbreviation: PCD, foreign language full name: kodak P hoto CD), the file extension is. pcd is a Photo CD file format developed by Kodak, which can only be read by other software systems. This format uses the YCC color model to define the colors in the image. The YCC and CIE color spaces contain many more colors than the RGB and CMYK colors of monitors and printing devices. PhotoCD images are mostly of very high quality. DXF format drawing exchange format (foreign language abbreviation: DXF, foreign language full name: D rawing e X change format), the extension is. dxf is the graphics file format in AutoCAD. It stores graphics in ASCII mode and is very accurate in expressing the size of graphics. It can be called and edited by large software such as CorelDraw and 3DS. UFO format is a dedicated image format of the famous image editing software Ulead Photolmapct, which can completely record all image attributes processed by Photolmapct. It is worth mentioning that UFO files use objects instead of layers to record image information. EPS format Encapsulated Page Description Language (foreign language abbreviation: EPS, foreign language full name: Encapsulated Post Script) is a cross-platform standard format, and the extension on the PC platform is. eps, on the Macintosh platform. epsf, mainly used for the storage of vector images and raster images. The EPS format is described in the PostScript language and can save other types of information, such as multiple tone curves, Alpha channels, color separations, clipping paths, screen information, tone curves, etc., so the EPS format is often used for printing or print output. Multiple EPS format options in Photoshop enable comprehensive control over printing, and in some cases are even better than the TIFF format. AI format The AI ??format is a vector graphics file suitable for Adobe's ILLUSTRATOR output format. Like PSD format files, AI is also a layered file. Each object is independent and has its own attributes, such as size, shape, outline, color, position, etc.

Files saved in this format are easy to modify, and files in this format can be output at the highest resolution at any size. Its compatibility is relatively high, it can be opened in CorelDRAW, and CDR format files can also be exported to AI format. PNG format Portable Network Graphics (abbreviated as PNG in foreign languages, full name in foreign languages: Portable Network Graphics), is the latest image file format accepted on the Internet. PNG can provide lossless compressed image files that are 30% smaller than GIF. It provides both 24-bit and 48-bit true color image support as well as many other technical supports. Since PNG is very new, not all programs can use it to store image files, but Photoshop can handle PNG image files and can also store them in the PNG image file format. Pros: PNG supports high levels of lossless compression. PNG supports alpha channel transparency. PNG supports gamma correction. PNG supports interlacing. PNG is supported by the latest web browsers. Disadvantages: Older browsers and programs may not support PNG files. As an Inter file format, PNG provides less compression than the lossy compression of JPEG. As an Inter file format, PNG does not provide any support for multiple image files or animation files. The GIF format supports multiple image files and animation files. HDRI format high dynamic range imaging (foreign language abbreviation: HDRI, foreign language full name: High Dynamic Range I imaging) HDRI file is a kind of file, the extension is hdr or tif format, has enough ability to save lighting information, but not necessarily It's a panorama. Dynamic Range refers to the relative ratio between the brightest and darkest parts of a scene. An HDR image records the brightness value of the actual scene far beyond the 256 levels, and the excess cannot be displayed on the screen. HDRI has a larger brightness range than ordinary RGB format images (only 8-bit brightness range). The maximum brightness of a standard RGB (red, green, blue) image is 255/255/255. If such an image is used in combination with radiosity to illuminate a scene, even the brightest white is not enough to provide enough illumination to simulate reality. In the world, the rendering results will look flat and lack contrast because this image file describes the wide range of lighting information in reality with only an 8-bit RGB image. RAW format The Chinese explanation of RAW is "raw materials" or "unprocessed things". The RAW file contains all the photo information of the original image file after it is generated by the sensor and before it enters the camera image processor. Users can use certain specific software on PC to process RAW format images. Storage and Advantages By understanding the topic of color filtering arrangements, we should know that in traditional sensors, each pixel is only responsible for obtaining one color. Each pixel usually carries 10 or 12 bits of data (12 bits is most commonly used), and this data can be stored in a RAW file. The camera's built-in image processor performs interpolation operations on these RAW data, calculates the values ??of the three color channels, and outputs a 24-bit JPEG or TIFF image. Although TIFF files maintain 8 bits of information per color channel, their file sizes are larger than RAW (TIFF: 3 × 8-bit color channels; RAW: 12-bit RAW channels). JPEG reduces the file size by compressing the original photo file, but the compression comes at the expense of image quality. Therefore, RAW is a balance between the above two: it not only ensures the image quality and color of the photo, but also saves storage space (relative to TIFF). Some high-end digital cameras can output almost lossless compressed RAW files. Applicability Many image processing software can process RAW files output by the camera. These software provide adjustments to the sharpness, white balance, tone and color of RAW format photos. In addition, because RAW has 12-bit data, you can use software to extract photo details from the highlight or dark areas of RAW images that are impossible to find in JPEG or TIFF images with 8 bits per channel. Disadvantages RAW has an obvious disadvantage: with different camera brands and models, the RAW format they output is also different. Users must use specialized software provided by the manufacturer when processing RAW format images. This brings a lot of inconvenience to image processing. In addition, compared to images in JPEG and TIFF formats, it takes more time to open and process RAW files. In order to solve this problem, some digital cameras allow users to save photos in RAW and JPEG formats at the same time when taking photos. As cameras process images faster and memory cards become larger and cheaper, this will no longer be a hassle.

Simultaneous recording of JPEG and RAW format photos allows users to organize and edit photos (JPEG) using conventional image processing software; when it is necessary to obtain finely processed photos or to improve photo defects (such as incorrect white balance and lack of highlight/shadow details) At that time, users can use RAW to solve the problem. In addition, more and more third-party software manufacturers are producing image processing software with strong compatibility, allowing cameras of multiple brands and models to use the same software to process their output RAW photos, solving RAW compatibility issues. Sexual issues. Adobe Photoshop CS is one example. However, Adobe Photoshop CS does not provide comprehensive RAW processing settings like the manufacturer's specialized software. Insufficient compatibility is still the biggest obstacle limiting the development of RAW format. WMF format WMF (Windows Metafile Format) is a common element file format in Windows and is a vector file format. It has the characteristics of short files and stylized patterns. The entire graphics is often spliced ??together from independent components, and the graphics are often rough. FLIC format The Flic format was developed by Autodesk. FLIC is the collective name of FLC and FLI: FLI is the original animation file format based on 320×200 resolution, while FLC uses more efficient data compression technology, so it has better performance than FLI. With a higher compression ratio, its resolution has also been greatly improved. EMF format EMF (Enhanced Metafile) is a Windows 32-bit extended metafile format developed by Microsoft to make up for the shortcomings of using WMF. It is also a vector file format. Its purpose is to make metafiles more acceptable. ICO format Edit It is a Windows icon file format that can store icon files of a single pattern, multiple sizes, and multiple color plates. Illustrations are computer graphics with clear referential meanings. The desktop icon is the software identifier, and the icon in the interface is the function identifier. Illustrations have a standard set of sizes and attribute formats, and are usually small in size. Each icon contains multiple pictures of the same display, each picture having a different size and number of colors. An icon is a set of similar pictures, each with a different format. From this point on the illustration is three-dimensional. An icon has another feature: it contains a transparent area that shows through the desktop background beneath the icon. In terms of structure, the illustration is actually similar to McDonald's Big Mac burger. An icon is actually a collection of multiple pictures in different formats, and also contains a certain transparent area. Due to the diversity of computer operating systems and display devices, the size of the diagram needs to be in a variety of formats. When the operating system displays an icon, it will select the image in the icon that is most suitable for the current display environment and status according to certain standards. If you are using the Windows 98 operating system, the display environment is 800x600 resolution, 32-bit color depth, and the image format of each icon you see on the desktop is 256 colors and 32x32 pixel size. If under the same display environment, in the Windows XP operating system, the image format of these icons is: true color (32-bit color depth), 32x32 pixel size. The following is the standard icon format in various Windows operating systems: (Unit: size pixel-color) Windows 98 SE/ME/2000 48 x 48 - 256 32 x 32 - 256 16 x 16 - 256 48 x 48 - 16 32 x 32 - 16 16 x 16 - 16 Windows 32 - 256 24 x 24 - 256 * 16 x 16 - 256 48 x 48 - 16 32 x 32 - 16 24 x 24 - 16 * 16 x 16 - 16 * This format is not required in XP diagrams. Under Vista system, it can support up to 256 x 256. At the same time, non-standard ico format files also support irregular size storage. Note: Windows98/2000 is not compatible with 24 x 24 format graphics. You can open icons containing this image format in the relevant application software, but the operating system considers it invalid. You must ensure that the icons you design contain at least one of the image formats listed above to achieve good display results. If the operating system cannot find a specific image format in the icon, it always uses the closest image format to display it, such as reducing a 48 x 48 icon to a 24 x 24 pixel size. Of course, the effect is worse. Icon file format In the Windows operating system, the file name suffix of a single icon is .ICO.

Illustrations in this format can be browsed directly in the Windows operating system; the suffix is ??.ICL, which represents the icon library. It is a collection of multiple icons. Generally, operating systems do not directly support files in this format and require the help of a third party. software to browse. In the graphical user interface, all resources in the system are represented by three types of icons: application icons (pointing to executable programs that specifically complete a certain function), folder icons (pointing to storage for other applications) A "container" for a program, document, or subfolder) and a document icon (which points to information created by an application). In Windows, the icon with a curved arrow in the lower left corner represents a shortcut. Shortcut is a special file type that provides quick and easy access to some resource objects in the system. The shortcut icon is a "stand-in" icon for the original object. Shortcut icons are extremely useful and are the primary way to customize your desktop and provide quick access to frequently used applications and documents. Application method Edit ico can be displayed as the first icon in the browser, and can also display a small icon in the first paragraph of the favorite content. Production Process Edit As long as you have a jpg, gif, or png picture, you can convert it to ico online. Or first use image processing software such as PS to make the picture look the way you want, that is, the surrounding area is transparent, and then save it in the "PNG" format. Download the software axialisiconworkshop[1], which is very useful. Open this software, File-Open, open the picture in "png" format, then the first tool on the middle picture (it is an "I" shape, put the mouse on it, it says "Create WINDOWS icon from image" ) After clicking, three options will appear: "Other image formats, OK, Cancel") Select OK, and then save ctrl+s.