I've been looking for a nice way to tag a large collection of photos and upload it to Piwigo.

Digikam has a nice tagging system, but with ubuntu 10.10 I tried 1.6 and 1.8 and couldn't get the tags to transfer.  Shotwell also has a nice tagging system and the ability to upload to Piwigo, but alas again no tags. At least that's what the web page says.

Picasa seems to have some support through IPTC metadata and a tweak to piwigo, but the tagging system seems very awkward.  At least I couldn't figure out how to easily add/remove tags to an arbitrary subset of photos.

Does anyone know of an alternative that allows for nice tagging (not requiring typing the name of each tag for each photo) and can upload to Piwigo while preserving tags?

Alternatively if there's a plugin for Piwigo that makes it easy to select a collection of images and add/remove a tab that could work as well. 

Another possibility would be if Piwigo supported some kind of tag import, I suspect I could write a script to read the metadata from shotwell or digikam for the tags and write it in a format that piwigo could import.