+Updated, June 2014: integrated changes from [[KathrynAndersen]],
+Lukas Lipavsky and kjs
+
+An `album6` branch is also available, but is less suitable
+for manual installation since it needs core IkiWiki changes
+(until [[bugs/trails depend on everything]] is fixed).
+
+### Manual installation
+
+First, you need a version of ikiwiki with the [[trail]] plugin merged in
+(version 3.20120203 or later).
+
+Manual installation requires these files (use the "raw" link in gitweb
+to download):
+
+* [album.pm](http://git.pseudorandom.co.uk/smcv/ikiwiki.git/blob/album5:/IkiWiki/Plugin/album.pm)
+ in an `IkiWiki/Plugin` subdirectory of your configured `plugindir`
+* [albumviewer.tmpl](http://git.pseudorandom.co.uk/smcv/ikiwiki.git/blob/album5:/templates/albumviewer.tmpl),
+ [albumitem.tmpl](http://git.pseudorandom.co.uk/smcv/ikiwiki.git/blob/album5:/templates/albumitem.tmpl),
+ [albumnext.tmpl](http://git.pseudorandom.co.uk/smcv/ikiwiki.git/blob/album5:/templates/albumnext.tmpl) and
+ [albumprev.tmpl](http://git.pseudorandom.co.uk/smcv/ikiwiki.git/blob/album5:/templates/albumprev.tmpl),
+ in your configured `templatedir`, or a `templates` subdirectory of your wiki repository
+* the album-related bits from the end of the
+ [stylesheet](http://git.pseudorandom.co.uk/smcv/ikiwiki.git/blob/album5:/doc/style.css)
+ (put them in your local.css)
+
+## Changing the templates
+
+When a viewer page is generated or inlined into an album, the template can
+contain these extra variables:
+
+* `<TMPL_VAR ALBUM>` - page name of the album
+* `<TMPL_VAR ALBUMURL>` - relative URL to the album
+* `<TMPL_VAR ALBUMTITLE>` - title of the album, usually taken from
+ a [[ikiwiki/directive/meta]] directive
+* `<TMPL_VAR CAPTION>` - caption for the image
+* `<TMPL_VAR THUMBNAIL>` - a small [[ikiwiki/directive/img]] for the image
+* `<TMPL_VAR IMAGEWIDTH>` - width of the full-size image in pixels
+* `<TMPL_VAR IMAGEHEIGHT>` - height of the full-size image in pixels
+* `<TMPL_VAR IMAGEFILESIZE>` - size of the image, e.g. `1.2 MiB`
+* `<TMPL_VAR IMAGEFORMAT>` - format of the image, typically `JPEG`
+
+The template for the viewer page can also contain:
+
+* `<TMPL_VAR IMG>` - a large [[ikiwiki/directive/img]] to display the image
+* `<TMPL_VAR PREV>` - a link to the previous viewer, typically with a
+ thumbnail
+* `<TMPL_VAR NEXT>` - a link to the next viewer, typically with a
+ thumbnail
+
+## Including album entries elsewhere
+
+To display images from elsewhere in the wiki with the same appearance as
+an [[ikiwiki/directive/album]] or [[ikiwiki/directive/albumsection]],
+you can use an [[ikiwiki/directive/inline]] with the `albumitem`
+template:
+
+ \[[!inline pages="..." sort="-age" template="albumitem"]]
+
+## Bugs
+
+* There's currently a hard-coded list of extensions that are treated as
+ images: `png`, `gif`, `jpg`, `jpeg` or `mov` files. More image and video
+ types could be added in future.
+
+* Videos aren't currently handled very well; ideally, something like
+ totem-video-thumbnailer would be used.
+
+* The plugin doesn't do anything special to handle albums that are subpages
+ of each other. If, say, `debconf` and `debconf/monday` are both albums,
+ then `debconf/monday/p100.jpg` will currently be assigned to one or the
+ other, arbitrarily. It should probably pick the closest (longest) album name.
+ (I'm not sure that it can do this reliably, though, since the scan stage
+ runs in an undefined order.)
+
+* The plugin doesn't do anything special to handle photos with similar names.
+ If you have `p100.jpg` and `p100.png`, one will get a viewer page called
+ `p100` and the other will be ignored. (I'm not sure what we could do better,
+ though.)
+
+* If there's no `albumimage` in a viewer page, one should probably be appended
+ automatically.
+
+## TODO
+
+* The generated viewer page should extract as much metadata as possible from
+ the photo's EXIF tags (creation/modification dates, author, title, caption,
+ copyright). [[smcv]] once had a half-written implementation which runs
+ `scanimage` hooks, and an `exiftool` plugin using [[!cpan Image::ExifTool]]
+ as a reference implementation of that hook, but has lost that code somewhere :-(
+
+* There should be an option to reduce the size of photos and write them into
+ an underlay (perhaps just the transient underlay), for this workflow:
+
+ * your laptop's local ikiwiki has two underlays, `photos` and `webphotos`
+ * `photos` contains full resolution photos with EXIF tags
+ * for each photo that exists in `photos` but not in `webphotos`, the album
+ plugin automatically resamples it down to a web-compatible resolution
+ ([[smcv]] uses up to 640x640), optimizes it with `jpegoptim`, strips out
+ all EXIF tags, and and writes it into the corresponding location
+ in `webphotos`
+ * `webphotos` is what you rsync to the web server
+ * the web server's ikiwiki only has `webphotos` as an underlay
+
+* Eventually, there could be a specialized CGI user interface to batch-edit
+ all the photos of an album (so for each photo, you get an edit box each for
+ title, author, copyright etc.) - this would work by making programmatic
+ edits to all the `albumimage` directives.