QQ？ Because there are many people in QQ space, it is congested. It is best to upload photos in the morning or at noon. Gipng is a compressed format of pictures.

Picture format: raster picture

BMP:Windows bitmap

Windows bitmaps can store a single raster image of any color depth (from black and white to 24-bit color). Windows bitmap file format is compatible with other Microsoft Windows programs. It does not support file compression, nor does it apply to web pages.

Generally speaking, the disadvantages of Windows bitmap file format outweigh the advantages. To ensure the quality of photo images, please use PNG files, JPEG files or TIFF files. BMP file is suitable for wallpaper in Windows.

Advantages:? BMP supports 1 bit to 24-bit color depth.

BMP format is widely compatible with existing Windows programs (especially older programs).

Disadvantages:? BMP does not support compression, which will make the file very large.

The Web browser does not support BMP files.

Pcx: computer brush

PC brush pictures (also known as Z-Soft bitmaps) store a single raster image at any color depth. Brush drawing is more widely used in early Windows programs and programs based on MS-DOS. Brush drawing is compatible with many newer programs. PCX pictures support RLE internal compression.

Advantages:? PCX is a standard format between many Windows-based programs and MS-DOS-based programs.

PCX supports internal compression.

Disadvantages:? Web browser does not support PCX.

PNG: portable network graphics

PNG pictures store a single raster image at any color depth. PNG is a platform-independent format.

Advantages:? PNG supports advanced lossless compression.

PNG supports alpha channel transparency.

PNG supports gamma correction.

PNG supports interleaving.

The latest web browsers support PNG.

Disadvantages:? Older browsers and programs may not support PNG files.

As an Internet file format, PNG provides less compression than JPEG lossy compression.

As an Internet file format, PNG does not support multi-image files or animation files. GIF format supports multi-image files and animation files.

JPEG: Joint Photographic Experts Group

JPEG pictures store a single raster image in 24-bit color. JPEG is a platform-independent format that supports the highest level of compression. However, this compression is lossy. Progressive JPEG files support interleaving.

You can increase or decrease the compression level of JPEG files. However, the file size is at the expense of image quality. The compression ratio can be as high as 100: 1. (JPEG format can easily compress files at the ratio of 10: 1 to 20: 1, and the image quality will not decrease. ) JPEG compression can handle realistic photographic works well. However, JPEG compression can not provide ideal results for simple works with few colors, strong contrast, solid color borders or large solid color areas. Sometimes the compression ratio is as low as 5: 1, which seriously loses the integrity of the picture. The reason for this loss is that JPEG compression scheme can compress similar tones well, but JPEG compression scheme can not deal with strong differences in brightness or solid color areas well.

Advantages:? Photographic works or realistic works support advanced compression.

The file size can be controlled by variable compression ratio.

Support interleaving (for progressive JPEG files).

JPEG widely supports Internet standards.

Disadvantages:? Lossy compression will reduce the quality of the original image data.

When you edit and resave a JPEG file, JPEG will mix the quality of the original picture data. This decline is cumulative.

JPEG is not suitable for simple pictures with few colors, similar colors in a large area or obvious brightness difference.

GIF: graphic interchange format

GIF pictures store single raster image data or multiple raster image data in 8-bit colors or 256 colors. GIF pictures support transparent, compressed, interlaced and multi-image pictures (animated GIF).

GIF transparency is not alpha channel transparency, so it cannot support translucent effect. GIF compression is LZW compression, and the compression ratio is about 3: 1. GIF89a version of GIF file specification supports dynamic GIF.

Advantages:? GIF widely supports Internet standards.

Support lossless compression and transparency.

Animation GIF is very popular, and it is easy to make with many GIF animation programs.

Disadvantages:? GIF only supports a 256-color palette, so detailed pictures and realistic photographic images will lose color information, but they look tonal.

In most cases, lossless compression is not as good as JPEG format or PNG format.

GIF supports limited transparency and has no translucent effect or fading effect (such as the effect provided by alpha channel transparency).

TIFF: tag image file format

TIFF stores a single raster image at any color depth. TIFF can be considered as the most widely supported graphic file format in the printing industry. TIFF supports optional compression and is not suitable for viewing in a Web browser.

TIFF format is an extensible format. This means that programmers can modify the original specification to add functionality or meet specific requirements. Modifying the specification may lead to incompatibility between different types of TIFF pictures.

Advantages:? TIFF is a widely supported format, especially between Macintosh computers and Windows-based computers.

Support optional compression.

Extensible format supports many optional functions.

Disadvantages:? The Web browser does not support TIFF.

Extensibility will lead to many different types of TIFF pictures. Not all TIFF files are compatible with all programs that support the basic TIFF standard.

Picture format: vector picture

DXF:AutoCAD graphic interchange file

DXF is a vector-based ASCII format used by Autodesk AutoCAD programs. AutoCAD can provide very detailed and fully extensible charts.

Advantages:? You can use AutoCAD to create very detailed and accurate charts and graphs.

AutoCAD files are very popular in architecture, design and sculpture industries.

Disadvantages:? The support of AutoCAD in Office is limited, and Office supports AutoCAD versions before R 12.

The learning curve of AutoCAD is steep. Please note that other graphics programs can also export DXF pictures.

Computer graphics metafile

CGM metafile can contain vector information and bitmap information. It is an international standardized file format used by many organizations and government agencies, including British Standards Institute (BSI), American National Standards Institute (ANSI) and US Department of Defense.

Advantages:? CGM is an international standard format.

CDR:CorelDRAW！

CorelDRAW！ Metafiles can contain vector information and bitmap information.

Advantages:? CDR is widely used in prepress industry and art design industry.

Disadvantages:? CDR has limited support in Office, and Office supports CorelDRAW! Version 6 and earlier.

WMF: window metafile

Windows metafile is a 16-bit Tu Tu metafile format, which can contain vector information and bitmap information. It is optimized for the Windows operating system.

Advantages:? WMF is a Windows standard format, which can be well used in office.

EPS: encapsulated PostScript

"Encapsulated PostScript" format is a special printer description language, which can describe vector information and bitmap information.

Advantages:? EPS can accurately render the effect on any PostScript printer.

EPS is an industry standard format.

Disadvantages:? The screen display may be inconsistent with the output display. The screen display may be low resolution, may be a different image, or just a placeholder image.

EPS file is used for output. They are not the most suitable formats for displaying information on the screen.

EMF: enhanced metafile

Enhanced metafile is a 32-bit format, which can contain vector information and bitmap information. This format is an improvement on the "Windows Metafile Format" and contains some extended functions, such as the following:

Built-in zoom information

Built-in instructions saved with the file

Improvements in color palette and device independence

The EMF format is extensible, which means that programmers can modify the original specification to add functions or meet specific requirements. This modification may lead to incompatibility between different types of EMF pictures.

Advantages:? Extensible file format

Compared with WMF, improved functions

Disadvantages:? Extensibility can produce many different types of EMF pictures, and not all EMF files are compatible with all programs that support EMF standards.

PICT: Macintosh pictures

PICT file is a 32-bit bitmap metafile format for Macintosh computers. PICT file uses RLE internal compression, and the effect is quite good. If QuickTime is installed, PICT files support JPEG compression (Macintosh only).

Advantages:? PICT is the best file format for Macintosh computer screen display.

PICT is the best output format when outputting from Macintosh computer to non-PostScript printer.

Disadvantages:? Fonts may not display correctly when moving between platforms.

QuickTime must be installed to view some PICT files correctly.

Resolution and color depth

This section discusses the appropriate color depth and resolution of raster images. If you save the picture with the correct resolution and color settings, a smaller file will be created. Smaller files mean smaller and faster documents and presentations. What you are most interested in is to make your pictures as small as possible within the requirements of picture use.

screen display

Number of colors, internet use, non-internet use

1 (black and white) GIF, with a resolution of 72 pixels per inch (ppi) GIF and a resolution of 72 pixels per inch (ppi).

16 GIF, resolution 72 ppi GIF, resolution 72 ppi.

256 (simple picture) * GIF resolution 72 ppi GIF resolution 72 ppi.

256 (complex image) * JPEG, with a resolution of 72 ppi JPEG and a resolution of 72 ppi.

Above 256 JPEG or PNG resolution 72 ppi JPEG, PNG or TIFF resolution 72 ppi.

Note: Microsoft recommends a resolution of 72 pixels/inch, because most monitors have a resolution between 60 pixels/inch and 80 pixels/inch. Saving at a higher resolution will not produce higher display quality, because your monitor cannot display more pixels than it actually does. You should calculate dots per inch according to the finished size of the picture, not the original size. For example, if you are scanning an 8.5 x 2-inch letterhead for a web page and the finished width is 2 inches, you can use 72 ppi to scan these 2 inches, totaling 144 pixels. When the size is set to 2 inches and displayed in the display viewer, the final file will look very good.

* Note: In 256 colors, JPEG files can provide a higher compression level than GIF files. However, JPEG compression is not as effective as GIF compression when compressing some simple files.

If your picture is a grayscale picture with a large solid color area, or an area with high contrast (there is a strong difference between bright and dark areas), choose GIF format.

If your picture is a color picture with many different colors (tones) and similar brightness or darkness (values), please choose JPEG format, because JPEG format can provide better compression. JPEG compression works according to hue, which is suitable for dealing with different hues with similar values. JPEG compression can't handle similar tones with different values well.

Print out

How to create a good printout is a complex topic, because there are many printers available, and each printer has different functions to generate color output and gray output. The main factor to produce good printout is the number of lines per inch (LPI) that the printer can print.

To print in color or grayscale mode, the printer must print in halftone mode. Midtones are arrays of points arranged in a grid, which represent each image pixel as a gray shadow. For dark gray, most points in the grid will be filled. For light gray, only a few points on the grid are filled. The LPI setting of the printer determines the size of the grid. The higher the LPI, the smaller the grid, and the less gray shadows the printer presents.

To print in color, the printer must print overlapping lines of color dots. Each point is set at a different angle from other points and will be slightly offset, so these points cannot completely cover each other. This unit of measurement is called "screen frequency" and is expressed by the rotation angle of the lines that make up the color points.

The following table can help you choose the best resolution for scanning, in dots per inch (dpi).

Printer Type Output dpi Output LPI Scan ppi

Laser printer 300 55-65 120

Laser printer 600 65-85 150

Inkjet printer 300 50-60 1 10

Dye printer 300 55-70 125

Imagesetter1250+120-150 300

To calculate the target scan resolution, you can multiply the LPI of the printer by 2. This is a universal law. To know the LPI of your printer, please refer to your printer documentation.

Note: When you apply the general rules of LPI Times 2, you must experiment. Some printers support very high resolution. If you save a picture with a resolution greater than 300 ppi, the larger picture may occupy a lot of disk space and slow down other operations on the computer. Multiple large pictures in the document may cause the program to stop responding, or Windows may stop responding.

The only exception to this rule is pure black and white images, that is, "line" images. These images use 1 bit to store color information. Please scan these images at the scale of 1 to 1. If your printer has a resolution of 600 dpi, please scan these images in line mode of 600 ppi.

If you want your pictures to be displayed in grayscale or less than 256 colors, please use TIFF format or GIF format. TIFF format is a graphic standard in printing industry, because TIFF format does not use lossy compression scheme. Other formats, such as JPEG, use lossy compression schemes. TIFF also supports multilayer transparency, and other formats rarely support multilayer transparency.

If the picture exceeds 256 colors, please save the picture in TIFF format or PNG format. If transparency is needed, Microsoft recommends using PNG format. If transparency is not required, please use TIFF format.

Microsoft recommends that you save the picture according to the printer resolution of the final picture size. For example, suppose you have an 8.5 x 2 inch letterhead, and you need to print a 2 inch letterhead. If your printer supports 600 dpi and 85 LPI, please set the resolution of the picture at 2 inches to 150 ppi, and you can get the size of 300 x 7 1 pixel.

term

Alpha channel: Alpha channel describes the transparent area in the picture. This transparent area allows the background to be displayed transparently. The Alpha channel allows more than 64,000 layers of transparent effects, so you can use translucent effects and mixed effects.

Color depth: Color depth is the number of colors in the picture. Color depth is classified by bit depth. If you use a deeper color depth, there will be more colors in the picture, but a deeper color depth will also increase the file size. ? 1 bit: black and white only

8 bits: 256 shades of gray or 256 colors.

16: high color, 65536 colors

24 bits: true color, 16,777,216 color.

32 bits: true color, 4,294,967,296 colors.

Compression: Compression is a mathematical scheme that makes picture files smaller by deleting redundant information. There are two types of compression: lossless compression and lossy compression.

Compression, lossless: lossless compression is a compression scheme that emphasizes maintaining the integrity of the original picture. When the picture is decompressed, it will maintain the same resolution and picture quality as the original uncompressed picture.

Compression, Lossy: Lossy compression is a compression scheme that emphasizes the generation of small picture files (even at the expense of picture quality). Compared with lossless compression, lossy compression can generate smaller picture files; However, when you decompress the picture, some original picture data will be lost and cannot be recovered.

File size: When you deal with picture files, the file size is the ultimate limiting factor. When working with pictures in Microsoft Office, file size is the most common cause of problems. The file size is determined by the following factors: picture size, resolution, file format, compression and color depth.

Gamma correction: this is a method to correct the brightness or darkness of a picture so that the picture is displayed with the same brightness on any display.

Hue: Hue describes the relative amount of red, green or blue in a color. For example, pink and crimson have red tones.

Interleaving: Interleaving is a method of sending picture data through the Internet. When a picture is interlaced, the following will happen: After downloading 1/64 of the picture, you can see the overall image of the appearance and shape of the picture. As more parts of the picture are downloaded, the resolution will increase until the whole picture is displayed.

Metafile pictures: Metafile pictures usually contain vector picture information. Metafile pictures can contain any type of picture data, such as raster pictures.

Palette: A palette is a list of colors that can be used for a specific picture. Different picture file formats have different maximum colors. If a picture contains more colors than those provided in a specific picture format, the extra colors will be replaced by the colors in the palette. Colors in the generated image may be distorted. This is called "palette effect".

Pixel: Pixel is the basic unit of measurement of a raster-based picture or monitor. Raster images and monitors are defined according to lines, and points of specific colors can be assigned to these lines separately. These points are called pixels.

Raster picture: Raster picture is a picture displayed by defining adjacent color point rows. Each point is assigned a separate color.

Resolution: Resolution is the amount of picture data in a specific picture area. Resolution is usually defined in pixels per inch. The higher the resolution, the more accurate and clear the image. However, when you increase the resolution, the file size of the picture will also increase.

Transparency: Transparency is a method that allows the image area to be displayed transparently, so the background can be displayed. There are many transparent methods, including alpha channel transparency.

Value: This attribute describes the brightness or darkness of the color. For example, pink and light blue have similar values, although they have different shades.

Vector diagram: A vector diagram consists of areas defined by coordinates and mathematical formulas. This file format is more general than raster image format because vector images can be scaled to any size. In some cases, vector pictures can be broken down into smaller components.

You can register an album online and upload pictures through the website.

Recommended: Netease photo album/