Should I put no follow on image pages?

[Turbosho]

Hi,
I have been slowly working on my website trying to make it easier to use and get better rankings again.
I recently remade my URL structure and got some awesome tips from some of the people in here.
I was reviewing what pages are indexed in google and it seems like some of my picture viewer pages are coming up. I was thinking maybe I should put a no-follow on them? Not only are they coming up on the google SE results but also on google images. I just don't want to cut my own foot. For a lot of the items that I search for a high percentage of the pages that come up are our image pages (a popup window) and then the category page, then once in a while the item page. Our picture viewer just has the picture, and a list of the thumbnails.
Right now when I do a search for:
Site:domain.com widget+547893xxy
I get:
Domain.com/id5-widget-547893xxy (this is the actual item page)
domain.com/pictureview/id5/widget-547893xxy (this is the picture viewer)
domain.com/sitemap/page3 (sitemap)
domain.com/cat24-black-widgets (the category of widgets)

Is this hurting me by having this many pages indexed? Will duplicate content hurt it? Google seems to like the picture viewer, it has that coming up for searches on quite a few items.

Any tips would be greatly appreciated.
Thanks!

[tedster]

First, be technically clear about what you are tagging. A nofollow attribute goes in the link pointing to the page, and a noindex meta tag would go on the page itself.

I don't think these pages are likely to hurt your rankings, but is it a good experience for someone to arrive directly at one of these picture viewer pages? Do they have some navigation available to browse more of your site?

[Turbosho]

Well it isn't a great experience but not horrible. All it has is one big picture, our logo up top, and if there is more than 1 pic for the widget there are thumbnails down the left side. When you click anything on the page(other than the thumbnails) it brings your back to the item page . My concern was that it might hurt the ranking of the item pages. I have seen our rankings slip over the past couple years and haven't been able to do much about it.

[aristotle]

1. Are the visitors to these picture viewer pages mostly coming from regular Google SERPs or from Google Image search?

2. Also, in the regular Google SERPs, do these picture viewer pages tend to rank above the corresponding item pages?

[Turbosho]

Most of the visitors are coming from the regular Google SERPs. In a lot of cases the pic viewer pages are ranking well above the item and category pages and in some cases the others don't come up at all. I also noticed that a lot of the widgets that don't have a pic were not indexed at all. So widget 52554 has a pic and comes up but the next one widget 52555 has no pic and isn't indexed at all.

[aristotle]

If the picture viewer pages don't have much textual content, in the regular Google SERPs they normally wouldn't rank above corresponding item pages that have a lot more textual content. Unless possibly

-- most of the content on the item pages is duplicated somewhere else on another site, or possibly

-- more internal or external links go to the picture viewer pages.

But those are just possibilities