Web Gallery Software

[memyselfandi]

Doing some stuff for someone and need to set up a non-internet facing web gallery for quite a large quantity of image files.

Image files have tags as their filenames, for example:
"house 2bed 2bath.jpg" or "bungalow 4bed 1bath.jpg"

I'd like to have it so that a search for a tag would dynamically produce a clickable contact sheet of all images matching that tag and the files be browsable as well.

Ideally the interface would look reasonably up to date. Their webserver is currently running a LAMP stack using Ubuntu Server 8.10.

Any suggestions about which gallery software may meet this criteria?

 

[memyselfandi]

It isn't a case that I want to have the tags in the filenames, that's where they already are

On going the tags don't need to be in the filenames but whatever gallery is used needs to have the existing tags in the filenames imported into it (and this process needs to be automated as there's too many files to manually type them in).