python image thumbnail generator?

[Chris Dewin]

Hi. I run a website for my band, and the other guys want an image gallery.

I'm thinking it would be nice and easy, if we could just upload a jpg into
a dir called "gallery/". When the client clicks the "gallery" link, a 
cgi script could search the gallery/ dir, and create thumbnails of any
jpeg images that don't already have a thumbnail associated with them. The
script could then generate a page of clickable thumbnails.

A few questions:

(1) Can this be done with python? If so, what module do I need to look up?

(2) If it can't be done with python, is there some small utility that will
do it for me? Something I could easily install locally in my own
"public_html" dir on my website?

(3) Is this the sort of thing which, if done regularly, would hog far far
too much of my webhosts system resources?

(4) Am I talking about re inventing the wheel?