Plugins are added and maintained via Lightroom's Plugin Manager, which is accessible from Lightroom's File menu, and also from a button on the Export Dialog itself.
Here's a screenshot of the Plugin Manager on my system, after I installed half a dozen plugins. At the moment, it's showing my “Metadata Wrangler” plugin selected. Mouseover the labels at left to highlight areas of the screenshot...
(Mouseover items below)
Installing a New Plugin
Installing a plugin for use with Lightroom 2 and later usually involves these steps:
- Downloading a zip file from a trusted plugin source.
- Unzip the plugin, and move the resulting “...lrplugin” folder to wherever you'd like to store your plugins.
- Bring up Lightroom's Plugin Manager and register that folder with the Add button.
(If prompted for a catalog update, do so.)
Installing a New Plugin
1. Download a zip file from a plugin source
After unzipping, you should end up with a folder whose name ends in “.lrplugin” or“.lrdevplugin”. On a Mac, a “.lrplugin” folder actually appears as a “module” package.
You don't normally ever need to be concerned with the contents of a plugin folder, but if you need to confirm that the folder actually contains a plugin in the first place, check for an “Info.lua” file. (On Macs, you may need to “Show Package Contents” in Finder to view the files inside.) I mention this because some programs that produce zip files create a “....lrplugin” folder into which they drop the actual plugin “.lrplugin” folder, which can cause confusion.
2. Move the plugin folder to wherever you'd like to store your plugins
Lightroom allows you to keep the plugins wherever you like — you just have to tell it where you place each one — so it's up to you to pick a spot to save them. Perhaps a "Lightroom Plugins" folder in your "Documents"?
When you "Add" the plugin to Lightroom, you're just adding a reference to the location. It's only natural to think that a copy of the plugin was made when you "Add", but Adobe doesn't do that, so be sure not to delete the plugin from disk.
3. Register the plugin with Lightroom
Bring up Lightroom's Plugin Manager, either from the File menu, or from the Plugin Manager button on the Export Dialog. Click the Add button, then navigate to the “.lrplugin” folder.
Some plugins add their own set of per-image metadata to the catalog, and for such plugins, you are prompted for permission to update the catalog upon install. You should upgrade.
For example, my “Upload to Flickr” plugin maintains in the catalog data about which images have been updated to Flickr, and their location at Flickr. This supports a number of features, such as the ability to replace an image during upload, the ability to filter within Lightroom for images that have/haven't been updated, the ability to include the Flickr-upload-status in Lightroom smart collections, etc.
You are also prompted in the same way when upgrading a plugin if the new version has any changes to the set of custom plugin metadata.
An export plugin can be selected by bringing up Lightroom's export dialog, then clicking on the “Files on Disk” banner across its top. That brings up a popup list of the export handlers available (both the built-in ones, and the ones you've added via the Plugin Manager)....
Some plugins aren't intended to be an export destination, but, rather, to provide generic support for any export. For example, my Metadata Wrangler plugin allows you to strip selected metadata from exported copies as they are produced. It can be used with the built-in “Export to Disk” standard export, with my “Export to....” plugins (e.g. Export to Flickr), or with other third-party export plugins.
Adobe calls these “Post-process Actions”, but most people call them “Export Filters”.
Once you've added and enabled a filter plugin via the Plugin Manager, it shows up in the lower-left of the export dialog....
Click on its name, then the Insert button at the bottom, and you'll see it added to the main dialog. In the screen snippet above, the “Metadata Wrangler” dialog section is shown collapsed, so you only see its banner. If you were to click on the little triangle beside the name, you'd see the full dialog for the plugin, which, in this case (my Metadata Wrangler filter) is huge (see here for a screenshot).
Plugin Maintenance & Upgrades
Once a plugin has been registered with Lightroom, you can enable or disable it from the Status section of the Plugin Manager. A disabled plugin can't be used from within Lightroom, but remains registered in the Plugin Manager, so can be easily enabled for use.
You can fully de-register a plugin with the Remove button, on the bottom of the left-hand column. Plugins installed in legacy plugin locations – the locations that plugins had to be installed for Lightroom 1.x – can't be removed this way, and the Remove button remains gray. You have to actually remove the folder.
The Status section might also display plugin version and web-site information, if the plugin provides it (such as in the screenshot above).
Upgrading a plugin
Upgrading a plugin to a newer version is similar to installing the first time, except that if you replace the original “.lrplugin” folder with the new one, you don't have to re-register the location with Lightroom. In that case, you simply need to restart Lightroom, or click the “Reload Plug-in” button in the Plugin-Manager's “Plug-in Author Tools“ section.
If you install the new version in a new location, and register it via the Plugin Manager, the previous version will remain, but be disabled. You can enable only one version of any particular plugin at a time. Simply Remove the older versions when you no longer need them.
I've built an upgrade mechanism into my plugins, such that when a new version is available, you can simply press the Upgrade Now button in the Plugin Manager. That causes the new version to be downloaded and unzipped in place over top of the old version. You then press the Reload Plug-in button, or restart Lightroom, to have the new version take effect.
(If something goes wrong with the upgrade process, you'll have to manually download and install the new version. In such a case, you might want to inspect the log file left in the temporary-files area of the system, named for the plugin, e.g. “flickr-log.txt” for the Flickr plugin).
If Lightroom 2.0 finds a plugin in any of the legacy install locations from Lightroom 1.x (described here), they are automatically registered with the Plugin Manager.
As with any plugin, such auto-registered plugins can be enabled and disabled within the Plugin Manager. They can not, however, be fully de-registered (removed) via the Plugin Manager. To remove them completely from Lightroom, you have to manually remove the plugins from disk (or, at least, from the legacy plugin folders).
Some people prefer to continue to use the legacy install locations, simply adding new plugins there (thereby avoiding the need to register them with the Plugin Manager). This approach is perfectly acceptable, of course, but comes with the drawback that added plugins are not auto-registered except when Lightroom starts.
Please do not report bugs or other comments related to my plugins here. Please do those on the appropriate per-plugin page (linked from my Lightroom Goodies page).