+
+> Putting a JPEG in the web form is not an option from my point of
+> view :-) but perhaps there could just be a "web-editable" flag supplied
+> by plugins, and things could be changed to respect it.
+>
+> In a way, what you really want for metadata is to have it in the album
+> page, so you can batch-edit the whole lot by editing one file (this
+> does mean that editing the album necessarily causes each of its viewers
+> to be rebuilt, but in practice that happens anyway). -s
+>
+>> Yes, that would make some sense.. It also allows putting one image in
+>> two albums, with different caption etc. (Maybe for different audiences.)
+>>
+>> It would probably be possible to add a new dependency type, and thus
+>> make ikiwiki smart about noticing whether the metadata has actually
+>> changed, and only update those viewers where it has. But the dependency
+>> type stuff is still very new, and not plugin friendly .. so only just
+>> possible, --[[Joey]]
+
+----
+
+Trying to use the "special extension" design:
+
+Suppose that each viewer is a JPEG-or-GIF-or-something, with extension
+".albumimage". We have a gallery "memes" with three images, badger,
+mushroom and snake.
+
+> An alternative might be to use ".album.jpg", and ".album.gif"
+> etc as the htmlize extensions. May need some fixes to ikiwiki to support
+> that. --[[Joey]]
+
+Files in git repo:
+
+* index.mdwn
+* memes.mdwn
+* memes/badger.albumimage (a renamed JPEG)
+* memes/badger/comment_1._comment
+* memes/badger/comment_2._comment
+* memes/mushroom.albumimage (a renamed GIF)
+* memes/mushroom.meta (sidecar file with metadata)
+* memes/snake.albumimage (a renamed video)
+
+Files in web content:
+
+* index.html
+* memes/index.html
+* memes/96x96-badger.jpg (from img)
+* memes/96x96-mushroom.jpg (from img)
+* memes/96x96-snake.jpg (from img, hacked up to use totem-video-thumbnailer :-) )
+* memes/badger/index.html (including comments)
+* memes/badger.jpg
+* memes/mushroom/index.html
+* memes/mushroom.gif
+* memes/snake/index.html
+* memes/snake.mov
+
+ispage("memes/badger") (etc.) must be true, to make the above rendering
+happen, so albumimage needs to be a "page" extension.
+
+To not confuse other plugins, album should probably have a filter() hook
+that turns .albumimage files into HTML? That'd probably be a reasonable
+way to get them rendered anyway.
+
+> I guess that is needed to avoid preprocess, scan, etc trying to process
+> the image, as well as eg, smiley trying to munge it in sanitize.
+> --[[Joey]]
+
+do=edit&page=memes/badger needs to not put the JPG in a text box: somehow
+divert or override the normal edit CGI by telling it that .albumimage
+files are not editable in the usual way?
+
+Every image needs to depend on, and link to, the next and previous images,
+which is a bit tricky. In previous thinking about this I'd been applying
+the overly strict constraint that the ordered sequence of pages in each
+album must be known at scan time. However, that's not *necessarily* needed:
+the album and each photo could collect an unordered superset of dependencies
+at scan time, and at rebuild time that could be refined to be the exact set,
+in order.
+
+> Why do you need to collect this info at scan time? You can determine it
+> at build time via `pagespec_match_list`, surely .. maybe with some
+> memoization to avoid each image in an album building the same list.
+> I sense that I may be missing a subtelty though. --[[Joey]]
+
+Perhaps restricting to "the images in an album A must match A/*"
+would be useful; then the unordered superset could just be "A/*". Your
+"albums via tags" idea would be nice too though, particularly for feature
+parity with e.g. Facebook: "photos of Joey" -> "tags/joey and albumimage()"
+maybe?
+
+If images are allowed to be considered to be part of more than one album,
+then a pretty and usable UI becomes harder - "next/previous" expands into
+"next photo in holidays/2009/germany / next photo in tagged/smcv / ..."
+and it could get quite hard to navigate. Perhaps next/previous links could
+be displayed only for the closest ancestor (in URL space) that is an
+album, or something?
+
+> Ugh, yeah, that is a problem. Perhaps wanting to support that was just
+> too ambitious. --[[Joey]]
+
+Requiring renaming is awkward for non-technical Windows/Mac users, with both
+platforms' defaults being to hide extensions; however, this could be
+circumvented by adding some sort of hook in attachment to turn things into
+a .albumimage at upload time, and declaring that using git/svn/... without
+extensions visible is a "don't do that then" situation :-)
+
+> Or extend `pagetype` so it can do the necessary matching without
+> renaming. Maybe by allowing a subdirectory to be specified along
+> with an extension. (Or allow specifying a full pagespec,
+> but I hesitate to seriously suggest that.) --[[Joey]]
+
+Ideally attachment could also be configured to upload into a specified
+underlay, so that photos don't have to be in your source-code control
+(you might want that, but I don't!).
+
+Things that would be nice, and are probably possible:
+
+* make the "Edit page" link on viewers divert to album-specific CGI instead
+ of just failing or not appearing
+* some way to deep-link to memes/badger.jpg with a wikilink, without knowing a
+ priori that it's secretly a JPEG