Creating an artists website-setting up Gallery

Hello,
I have been redoing my fine art website using this theme, I'm VERY new to WP but love this theme and the support. I am not used to touching code and have just tweeked the site using the great page of editable boxes that Flynn has developed.
I have searched every post on the forum but can't really find much on developing a gallery for artwork. I need my artwork to start from one Gallery (page at the top), then divide into about 11 sections or thumbnails, each will have it's own body of art...(ex. landscapes, portraits, nature...) each of these pages must show thumbnails that can be clicked and take you to an individual 'post' I think. I need them to show on their own page so I can edit, put prices, paypal buttons and text about the painting. It'd be nice to allow comments. I hope this doesn't sound too confusing..one page of thumbnails ...leads to another page of thumbnails..to finally posts.

I am trying to understand the differences still between pages and catagories? I don't want to start much until I understand. I have the site up if you'd like to look http://www.marymcandrew.com
I love the rotating header for my artwork!!! just love it, every time you click a page, a random artwork comes up!
thanks so much for any advice,
Mary