I have used this plugin quite a bit for a little while now and have never had this issue before... I have mapped the www/non-www and made the www version the primary. But if I type in just domain.com it doesn't redirect to http://www.domain.com and the links to images are broken.
However clicking any link will redirect to the www URL. This is the first domain I have mapped using this install of multi-site, so I don't know if there's something messing with it internally or if the DNS isn't set properlly. Instead of setting an A or CNAME record in the registrar I just change the DNS itself. Is that incorrect? It's worked in the past... :P
There must be something I have missed here and I couldn't find a similar post in the support forums. If anyone has any answers that would be a huge help :)