I have one link in main nav
example.com/photo but i want to add more links on page, which go on same page as this nav.
example.com/photo# help me avoid duplicate link to same page?
Duplicate links is not an SEO issue unless someone is doing page rank sculpting, in which case use
rel=nofollow on the duplicate link (though I really wouldn't bother as I don't think this works any more, and it was of negligible benefit when it did.)
If you mean is a
# on the end of a URL counted as a separate page, then no it is not. It is an anchor to the same page.
Even if it did count as a separate link, Google would just choose one of them as canonical.
You can have two or more links from one page A to a page B. There is no issue here. You are not going to be penalized. There is no need to avoid duplicate links to same page. Your SEO guy is wrong.