I believe there is an issue with 3.0.3 and images. I know I don't get thumbnails, but I haven't tested it extensively.
Did vB recognize GD and does it work with other attachments? Remember, you still will have to rebuild the thumbnails under Update Counters in the admincp. Even with all that and after searching in this thread for "thumbnails", it seems as if the thumbnails do have a problem with any version higher than 3.0.1. Someone mentioned redoing the code so a text link would show, but I didn't look for it.
John has stopped in once people started getting testy, but he is quite busy on other projects, so he won't be able to help in the near future. But the good thing is, he's working on a new version even better than this one.
As as aside, I didn't realize you were all the way in Athens, Greece! I lived for a few years in a small town called Athens in the state Alabama here in the USA. We once got a piece of mail that was misdelivered to Athens, Alabama instead of Athens, Greece, lol. And the confusion is even more when all the neighboring states also have a town called Athens--Athens, Georgia; Athens, Tennessee; Athens, Mississippi.