I have a sister named 'Jo' and a son in law named 'Joe'. Each has been tagged in separate pictures.
Is there any way I can do a search and only get items tagged 'Jo'?

You can enable which fields (=db columns) search should search for the term on the search options. You can also select individually which of these should be used on the default search field with the default search form on themes.

Otherwise tags also have an url: yourdomain.com/page/search/tags/jo/

Thank you so much for your rapid response-- I set the "Tag matching" to 'exact' from 'partial' and it now works as I want. I don't know how I missed that before. Again, thanks. I love zenphoto.

Great, thanks!