I guess it really comes down to what key phrase you are trying to rank, adding new pages with unique copy doesn't mean they will rank automatically, apart from onsite factors, you need to look into external factors as well, this includes building links to the new pages or taking advantage of social signals (if this applies to your industry).
To see whether there is any duplicate copy issue, I recommend using this http://www.copyscape.com, you can check whether there are any duplicate copy floating around on the net.
In regards to the flickr images, it really depends on the alt tag, how they describe the images, I don't think there is a problem using the same images on different pages with the same alt tags but if alt tags are all keywords, that might be a problem.
In regards to link building, my recommendation is to link to the page that would benefit users the most because apart from getting traffic in, I look into getting them to the most useful page to get them to convert, and I believe Google likes this more than just ranking the homepage. So if you find the "not-ranking" page beneficial to users, I would link to it and it will help get them indexed/ranking. One other thing you need to look into is the quality of the link, make sure it's relevant to your industry, because if they are just random links, Google might not pass value at all.
Hope this helps