NextGEN Gallery CDN w/ JetPack’s Photon

Jetpack has changed drastically since this article was written, and the Photon feature no longer transfers NextGEN Gallery's images to their CDN. It's now working intermittently, so this article is no longer valid. If you'd like to see Photon work with NextGEN Gallery, please get in touch with Jetpack.
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Some NextGEN Gallery users were wondering how to use a CDN (content delivery/distribution network) with the plugin.

Well, the good news is there is a free plugin out there that can get the job done for you.

If you're a user of JetPack then all you have to do is enable the Photon feature.   If you're not already using the plugin, do a search for JetPack and activate it on your site.

Here is a video with more details:

As mentioned in the video, be sure to deactivate any of the JetPack features you do not need. Also, it is uncertain how long the Photon CDN feature will remain free. That, of course, is up to the Automattic team.

Notes From Our Developers

• Photon is only allowed to be used by sites hosted on WordPress.com, or on Jetpack-connected WordPress sites.
• All images are losslessly compressed using either OptiPNG or jpegoptim
• It's not just a delivery service, but also an image manipulation service - you can use Photon for resizing images, cropping (while optionally considering aspect ratio), filtering, adjusting brightness & contrast, and zoom levels.
• No cache invalidations. Currently images are cached forever.

There's an important but subtle difference between block storage like Amazon S3 and a CDN - a CDN is designed for caching and distribution, whereas a block storage service is meant to simulate something like a USB flash drive - an external drive that you can write to as if it were a local filesystem.

For instance, when a user uploads an image, the original full-sized image would be stored as filename.jpg. Now let's say a user applies watermarking to that image, which modifies the filename.jpg file. There's no way to tell Photon to "refresh" - once the image is cached, it's cached indefinitely. Most other CDNs are better than that; they at least cache the image for a specified amount of time (called the time-to-live value, or TTL), so that any changes made to an image will eventually be propagated to all servers of the CDN.

Thanks for reading,

Scott