Linux is a free operating system, its purpose the same as for example MS Windows and Mac OSX. There are many reasons to use it, although I currently don't! I think it especially shines for getting the most out of older hardware, you can really customise and optimise it without having so much required bloat.
You can have multiple operating systems installed on the same computer at the same time by the way, which I did for a long time.
imgal is a script I wrote to help maintain this site. It automatically creates an html gallery from a directory of images. Linux only! Don't use this anymore, as I now use DokuWiki.