Is it possible to integrate in the next version of zenphoto the repair of the canonical url :

• If you want to redirect http://www.example.com to http://example.com, you can use this:
  RewriteCond %{HTTP_HOST} ^www.example.com$
  RewriteRule ^/?$ "http\:\/\/example.com\/" [R=301,L]
• If you want to redirect http://example.com to http://www.example.com, you can use this:
  RewriteCond %{HTTP_HOST} !^www.example.com$ [NC]
  RewriteRule ^(.*)$ http://www.example.com/$1 [L,R=301]

There is nothing to repair or fix for Zenphoto here. How you want to handle www to non www or vice versa domain redirection is your personal decision on your own server. Most hosts let you even do this domain redirection conveniently via the host backend so you don't even need to use htaccess.