I installed this contributions v2.2 yesterday and had the problem where it wasn't creating the thumbnails in my store. It was creating them in the admin section but not in the store. I tried all the suggestions and nothing worked. oscommerce is installed in the root folder.
Well I finally got everything working great today and here's what I did:
There are two versions of the Product_Thum.php file, one for the admin and one for the catalog.
What I did is install the one for the admin section to both the admin and catalog and that's it!
I've checked it on several different computers, all work great. The thumbnails are being created in the thumbnails/ directory.
My only question is, do I have to manually empty that thumbnails/ folder periodically or will it be done automatically? I don't want to keep inflating the size of my server.
I really hope this helps.
Viz