Good free web album: suggestions?

What I'm looking for is a freeware/open source web album tool that allows me to put pictures on my server, so that I can refer to them as a web album with a url as www.mydomain.nl/category/albumname/.

SimpleViewer is such a program. In addition to the functionality this tool offers, however, I would like to be a able to customize image and thumb nail size. An option to show an image full size (original size) per mouse click on the album image would be nice too.

Does any of us have experience with such a program?

Three come to mind...
Coppermine, Gallery, and a perl program called Album.pl

Thank you! I'll have a look into them.

Someone else pointed me to various Drupal solutions, but those seem to be require a bit more knowledge.

+1 for gallery2

I've used both Coppermine and Gallery. Coppermine is simpler, but Gallery is more powerful, at least in my opinion. There are many user created themes that you can use for Gallery and I think that it just looks a little more professional.