I built a 1/700 scale Gneisenau about a year ago (the Tamiya kit). I did a bunch of on-line research (my typical approach) and found a few pics, but as I recall, not a ton of stuff in color - I think there were a few paintings, but I don't recall any actual pics. I'll dig around and see if I still have any of it.
If you have not done it already, I would certainly suggest a google image search for both Gneisenau and Scharnhorst.
If I find any of my refs, I'll shoot them to you via PM in a day or so...