If you don’t want to use Jetpack’s image CDN, simply deactivate the Photon, Carousel, and Tiled Galleries modules.
The Photon CDN serves images off on an external server specially designed to serve just images and handle the dynamic re-sizing. There is absolutely no way it can slow down your server. If anything, it will make it faster since it no longer has to serve the image files.
The Mosaic gallery style and Carousel all serve the perfect image size to fit into the display size of the browser viewing the site at that moment. In order to prevent WordPress from eventually creating a few hundred different sized versions of the image or from serving a 2000×2000 image to an 800×600 screen, Photon is used to dynamically resize the images for each individual request.
http://jetpack.me/support/photon/
http://jetpack.me/support/tiled-galleries/
But I wanted JetPack specifically to create galleries. Unfortunately, I want to keep everything on my own server.
I understand that, in theory, parallel downloads should speed things up, but many reviews say otherwise. Now, that may be due to those reviewers having a theme or other plugin incompatibility; I couldn’t say.
But why the need for the WP server? Why would WP want to offer all that free data storage to millions of users? That costs the company money. And I would assume that eventually WP will want to be paid for the service, yes?
Also, I could not find anything to explain the terms of use for the Photon CDN. So I don’t know what the issues might be with potential sales or licences to third parties, much like FB does with photos posted to their free service.
This bit was why the galleries used Photon too:
“The Mosaic gallery style and Carousel all serve the perfect image size to fit into the display size of the browser viewing the site at that moment. In order to prevent WordPress from eventually creating a few hundred different sized versions of the image or from serving a 2000×2000 image to an 800×600 screen, Photon is used to dynamically resize the images for each individual request.”
That re-sizing happens on Photon’s servers, so it doesn’t take processing power or space on yours.
For terms details, you’ll need to contact the folks behind Jetpack: http://jetpack.me/contact-support/
