How do I allow visitors on my site to share my photos, on their Facebook wall/news feed?
I see that there is a "share" or "like" option from Facebook but that seems to share the whole page.
I would like to have it so that each picture has a small Facebook icon next to it and when they click it, that specific image only is added to their Facebook news feed/wall.
My site is in ASP.NET 3.5 using C#. I can develop in C# so if that is a route to what I am trying to achieve that is fine.
This should be what you're looking for. http://developers.facebook.com/docs/share However, do note that that is no longer the recommended way to do it. Soooo...
Use either the OpenGraph or the Like Button. The latter is the easier of the two.
edit- As an addendum if you look at the documentation for share and search for "Creating Your Own Share URL" (bottom of the page) you'll see how to construct the proper url.
http://www.facebook.com/sharer.php?u=<url to share>&t=<title of content>