What format is lossless for Photoshop pictures?

Photoshop exports pictures in the following five lossless compression formats, and the appropriate format should be selected according to the application scenario:

1. GIF.

GIF is encoded by LZW compression algorithm, which is a lossless image format based on index color. Due to lossless compression, compared with the old BMP format, it is smaller in size and supports transparency and animation.

The disadvantage is that since GIF only stores 8-bit indexes (that is, it can express 2 8 = 256 colors at most), pictures with complex colors and rich details are not suitable for saving in GIF format. Logo, icon and wireframe with simple colors are suitable for gif format.

2、PNG-8。

PNG-8 adopts lossless compression and is a bitmap format based on 8-bit index color. PNG-8 supports transparency better than gif, and its size is smaller at the same quality. It is very suitable as a substitute for gif.

but PNG-8 also has an obvious disadvantage that it does not support animation. This is also an important reason why PNG-8 can't completely replace gif. If there is no animation demand, png-8 is recommended to replace GIF.

3, PNG-24 and PNG-32.

both of them adopt lossless compression, which is a bitmap format based on direct color, showing opacity, while the PNG24 exported from Photoshop is actually png32. In addition, the picture quality of PNG-24 is comparable to that of BMP, but it has the size advantage that BMP does not have.

PNG-32 has four channels (red, green, blue and transparent) of RGBA, each accounting for 8bits, so it supports transparent pictures, and there is no difference compared with PNG-24.

these two formats are very suitable for saving source files or image formats that need secondary editing. Although it can express rich picture details like jpg, it cannot replace JPG.

4、TIFF。

TIFF is the abbreviation of Taggen Image File Format, which was originally designed for cross-platform storage of scanned images.

TIFF uses lossless compression and supports multi-color image modes. Because it stores a lot of image information and has high image quality, it is conducive to the reproduction of the original, and this format is used in many places for printing.

however, this format has poor compatibility and large volume, and is generally suitable for users of Mac system and photographers to do nondestructive scanning or print and publish.

4、WebP。

WebP image is a new image format, which was first released by Google in 21. Compared with PNG and JPG, the size of WebP image is reduced by about 3% under the same visual experience, and both lossy compression and lossless compression are provided.

in addition, the WebP image format also supports transparency and animation. Theoretically, it can completely replace PNG, JPG, GIF and other picture formats, and it is the best picture storage solution at present.

unfortunately, the WebP format has not been fully supported at present. In the latest version of Photoshop 219, files in WebP format are not supported by default, and WebP plug-ins need to be installed to open and edit normally.

Extended materials:

Summary of useful lossless image compression tools:

1. TinyPNG.

besides the online version, Tinypng also has a plug-in version, which can automatically compress the pictures in foreign trade websites. In short, it is very powerful.

2、Optimizilla。

Optimizilla and TinyPN can both compress up to 2 JPG or PNG pictures in batches at a time, and they can also be packaged and downloaded after compression. This tool supports Chinese browsing.

3、Resize Photos。

Resize Photos is a full-featured image compression tool. Before compression, you can set the width, quality (1 to 1, the smaller, the less clear) and format (supporting JPG, PNG, GIF, BMP) of the picture, and you can also add effects to the picture after compression.

4. Color pen.

Color Pen is a free online image compression gadget. This tool supports batch uploading of multiple files, and can easily optimize the size of PNG/GIF/JPG images to the limit.

The color pen is supported by professional algorithms, which can keep the definition the same as the original after the picture size is greatly reduced.

Baidu encyclopedia-image file format