[SGVLUG] Recommendations for a Web Photo Gallery

[James McDuffie]

I would like some recommendations for a web photo gallery app that meets
most of my requirements listed below:
* Open source
* Uses the photo files themselves to store meta data
* Does not require a web interface to upload and arrange files
* Reasonably mature and maintained
* Can also do video files
* Supports some sort of authentication
* Ability to specify which photos are public and which are private

I ask because for years I have been using Gallery 3, but I want to get
away from the fact that once you use an application such as this, your
metadata is sort of stuck should you want to switch to something else. I
did make a go at exporting my captions from Gallery but got stuck trying
to match some of the files I had imported with my archive of files. I
really want data portability. None of the most active image gallery
programs meet my requirements as far as I can tell.

I want to be able to manage my photos as files and be able to reorganize
them without confusing a web interface that overly relies on a database.
I've been using digiKam (http://www.digikam.org/) to manage my files
locally and have been using it in a way that writes all the captions and
tags to the files themselves. 

So in summary I would like a web front end that does not depend on how I
am managing my files. It should just display the files and if it does
have an administrative interface, write that information to the files
themselves.

Any ideas? I've Googled to no end and haven't yet found something to my
liking. I might just end up rolling my own.