oscommerce modification and gallery pages

I want to do some modification on oscommerse website 1. Category page point to an url that I specified 2. Create image gallery that I can display thumbnail and enlarged photos. There should be more than three categories for each photo. Upload is not necessary at least I need to enter file name or file path to populate the gallery. I currently have static gallery. 3 Create a few small thumbnails on the left column information box and category list that need to the urls that I specify. there are about 20 urls that I want to specify and link delivery includes functional pages, admin function or clear instruction for admin