lorax - 1:50 pm on Jan 30, 2013 (gmt 0)
Welcome to WebmasterWorld seotoka, we're glad to have you aboard.
I'd suggest you focus more on usability and be sure the images and copy are added with appropriate Alt and META data and leave it at that. With a site that large, especially if content is being added and removed, the products and images aren't as important individually. Their importance is at the category and site level so how you organize your content will matter most - IMHO. SO all of your SEO efforts would be focused at the category level pages including rich snippets etc.