I can also only recommend digikam.
I've switched to it years ago while migrating from Mac/iPhoto and I'm quit happy with it. It's easy to group, classify, comment and tag images, it supports easy geotagging and it's open in that it can store all these meta data in standard format in the image itself.
The last point is the most important for me, because this means I'm not locked in into using digikam.
And if I need to do something special with the meta-data outside of digikam I can also script my images outside of it and later make digikam read the changed meta data.
Posted Jun 17, 2010 10:22 UTC (Thu) by nix (subscriber, #2304)
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It's also open in that even its internal DB (maintained so it doesn't have to keep on rewriting images all the time) is a sqlite database, so easy to fiddle with outside of digikam.
Digikam
Posted Jun 17, 2010 10:32 UTC (Thu) by tzafrir (subscriber, #11501)
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Right. But try copying it from one computer to the other. It will loudly complain about invalid an UUID. It stores the UUID of the disk in the DB.
Digikam
Posted Jun 18, 2010 8:15 UTC (Fri) by buchanmilne (guest, #42315)
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In 1.3, the database can also be external (so, sharing photo meta-data between different machines is possible, if the photos are in a constant location, e.g. network share). At present only MySQL is supported, but more external databases will come.
Digikam is also available on Windows, and while there are a few small issues, works adequately, and is better than many of the free apps on Windows.