How is it possbile that the OTA sync for Zimbra does NOT get the pictures for the contacts which are on the server?

Originally I had pictures for contacts on my WM6, then I synced that with Outlook, saved the PST and imported it into Zimbra. On the web frontend I can see the pictures for the contacts, however when I sync to the device they don't appear.

Does anyone know how I can get this working?