WordPress and Jetpack Provide Free Image CDN Acceleration and Permanent Caching!

Jetpack Site Accelerator (also known as Jetpack CDN) can help speed up your pages by allowing Jetpack to optimize your images and deliver them along with static files (like CSS and JavaScript) from global servers.

At the same time, this service provider also provides free global CDN acceleration for images under any domain name. Images can also be accessed smoothly domestically! As a website owner, it's also quite a good solution for accelerating and backing up images.

WordPress and Jetpack Provide Free Image CDN Acceleration and Permanent Caching!

Accelerate Domains

i0.wp.com
i1.wp.com
i2.wp.com
i3.wp.com

Path Format

http://i0.wp.com/$REMOTE_IMAGE_URL

Image Address:

 https://i0.wp.com/img1.static.ruyo.cc/ali//kf/HTB1x1ylS9rqK1RjSZK9760yypXaL.png

File Formats

gif, png, webp, jpeg and jpg

What's Coming Up

Features

Open source! You an get it from SVN at http://code.svn.wordpress.org/photon/Trac: http://code.trac.wordpress.org/browser/photon

Fast! The site accelerator utilizes multi-level caching, including CDNs distributed globally, to ensure images are delivered as quickly as possible.

All images are dynamically compressed using a combination of pngquant and OptiPNG or jpegoptim. Lossless compression can be achieved by specifying a quality setting of 100 in the query parameters.

Multiple domains. To take advantage of parallel downloads, we support multiple subdomains for the site accelerator. If you tend to have many images per page, you can split them across i0.wp.com, i1.wp.com, i2.wp.com and i3.wp.com. Reusing the same subdomain in subsequent calls may be useful to leverage caching.

SSL support. You can use the site accelerator on SSL pages without mixed content warnings. Just use 

https://i{0,1,2,3}.wp.com

instead of 

http://i{0,1,2,3}.wp.com

Limitations

  • Accelerated images are "permanently" valid and cannot be deleted from the cache! Image replacement is not supported.
  • Images larger than 55M cannot be accelerated.
  • Scaling parameters are limited between 1 to 10.
  • Adjusting the path parameter can cause GIF animations to break.
  • In some cases, the official site may compress the original image for storage.

In conclusion

  • This is a very good acceleration method and domestic access speeds are also decent!
  • Private images should not be accelerated in case they cannot be deleted.
  • Currently, images under any domain can be accelerated, including those from major companies.
  • Acceleration will fail if your images have anti-leeching requests enabled.
  • The official site may delete accelerated images and blacklist domains if abuse is detected.
  • It's best to backup images in multiple ways just in case!