Open source Flickr-like app?

Zanguinar writes: I've been a Gallery user for years now. I have a ton of photos, organized by albums, mainly just for use by my family and close friends. However, some of my friends have begun using Flickr. I can't say I blame them. It's got a great design, and I love the tagging concept. However, I'm not eager to store my photos on somebody else's server, and don't want to pay for the privilege, especially since I already run my own web server. But I can't find any Flickr-like software to run on my home LAMP setup. All I want is to be able to tag my photos like Flickr and be able to display them by tag, tag intersection, date, etc. Why hasn't anybody published some OSS to do this yet?