Image format analysis

PNG

• png Is a kind of image format using lossless compression , therefore PNG The color expressiveness of pictures in this format is better than that of pictures in other formats .

JPG/JPEG

• A lossy compression format , Without affecting the quality of people's distinguishable pictures , Compress the file size as much as possible , It means JPG/JPEG Remove some of the original information from the picture . It can get better image quality with the least disk space .

WebP

• WebP Format is a kind of image format developed by Google to speed up image loading .WebP It provides lossless and lossy compression capability for network pictures , At the same time, it supports transparent channels under lossy conditions . According to official experiments ： Nondestructive WebP comparison PNG Reduce 26% size ; lossy WebP comparison JPG/JPEG Reduce 25%~34% Size ; lossy WebP Transparent channels are also supported , The size usually corresponds to PNG Of 1/3.
• Google browser is right WebP Besides better format support , Other browsers are right WebP The support of is obviously not good enough , This is also WebP One of the short boards .
  • Multiple suffixes are compatible ： Picture request has 2 Format suffixes , Namely JPG and WebP, This picture has 2 In the form of , Then the program determines whether it supports... According to the browser model WebP Format picture , If not, return JPG Format , If supported, return WebPack Format .
  • Appoint Accept Head support WebP Format