JAlbum will thumbnail all your images for you, and can then even FTP them to your website. You should take a look as it's pretty much a total solution...
http://jalbum.net/quickstart.jsp

Antonye's spot on with the JAlbum software, I checked out loads of others last weekend but JAlbum is way better than anything else i tried.
Adding the filters is a bit of a pain as you cant cut and paste the text in. It's all case sensitive too, but you only have to type stuff in once.

And its free.....................amazing!

Thanks chaps,

Will take a look at JAlbum then........