I used the new media manager and I sort of like it.
I think there's some flaw in the logic it uses for the creation of new "galleries" made of pictures attached to different posts.
The new media manager kinda suggests that you are "creating" a new entity called "gallery" while it's actually just merging together a bunch of images ids in a shortcode, saving you from the hassle of manually enter them in the text view.
I understand that you won't see the flaw if you are using the Carousel display from Jetpack, since it won't take you out of the current page and you won't need to get the image tied to that specific gallery you "created".
Nevertheless I think there's a dangerous gap between the UI of the new media manager and what it actually does to show a gallery which is especially clear when you want to get that "gallery" in a new attachment.php page.
You're left with functions that call images in relation only to the original post you're attached to.
The real solution would be the creation of a new "real" object "gallery" with its own ID.
A gallery entity could no more than a "group" of image ids, but it would be easier to manage:
- You could create it directly from the Media Manager, in the way you create the new "galleries" now in WP 3.5.x Instead of generating a shortcode like this: [gallery ids="xx, yy, zz"] it could simply create a new "Gallery" with its own id and call it like this: [gallery galley_id="123"]
- You would be able to manage your "real galleries" objects under media, in a new "Galleries" section
- You'd have a set of functions to manage such an object. In that way the problem would be solved just by passing the gallery_id to use in the attachment.php template (or a new gallery.php template that could be implemented as well) using the corresponding function.
- You'd be able to mix up pictures attached to various post in a gallery object without worrying about the original post.
- You could add multiple galleries to a post in a cinch and be sure they retain their "singleness"
If you think about it, this is NextGen galleries in a nutshell. No wonder people use that plugin a lot.
I don't think that such an important feature should be deferred to a plugin, especially a pretty bloated and heavy one like Nextgen, which packs a lot of superfluous features.
Hope I've been clear enough, English is not my first language. :)