In reply to Alec Kinnear.

It totally could be handled all locally. There's a Trac ticket to add this to Core: https://core.trac.wordpress.org/ticket/15311

In our particular case, the fancy galleries were already on WordPress.com and using WP.com's iteration of Photon. There are no plans to not use Photon on WordPress.com, Core doesn't support dynamic image sizing itself, Jetpack, generally, already requires a connection for most things to function, and Photon is easier on the local host than trying to spin up a number of different image sizes, so put it all together, it didn't make sense for us to spend dev time to perfect within Jetpack a second solution that wasn't as feature-rich as the original (the CDN aspect of Photon, for example).

That said, we do have a mostly functional fallback in Jetpack when there is not a connection (at the request of folks using Jetpack Development Mode), but it isn't perfect. I don't recall the details at the moment, but I believe crop and zooms are off on that. Good for getting a sense of how Tiled Galleries look, but may or may not be good enough for production.

Once there's a native solution in Core, I'm pretty sure we'd adapt Tiled Galleries to make use of it as an alternative, which would make it easier for folks to use without Jetpack and/or make it considerable for Core inclusion.

Our goal isn't to cripple anything. Jetpack Comments don't make sense for Core since they require API keys (the social network sign-on pieces) and, honestly, haven't improved much, if any, on our end since they were released on WP.com/Jetpack.

Anytime anything in Jetpack is reasonable for Core inclusion, we're 100% in support of that. 4.3's Site Icon is a good example of something from Jetpack being the beginning to enhance Core.

I'm cool to agree to disagree. The Jetpack team loves Core and why George and myself try to be as active on feature plugins and other core enhancements as we can be.

Cheers!