category images working 4 anyone?

its great that this hack exists, cheerz man.
but for some unexplainable reason i cant seem to get it to work ….
anyone else having trouble????
i did it exactly as it says in the instructions. and i tried many times over!
i even ended up changing my .gif icon images into .png files and put them into the exact proposed folder, but it keeps feeding me back a broken image tag.
would it be possible to use the category ID tag instead of the nicename somehow?
i have very limited knowledge of php, yet i suspect there lays my problem: the nice names…
if i tag the image with the ?php the_category_ID() ? tag the icons do show, but they somehow print very strangly = on two lines and with an additional written link.