Sorry, Phil, there is no way to prevent the thumbnails from being added to Eye-Fi Center or your online Eye-Fi account at http://center.eye.fi. It's a running history of your uploads. You can delete this history by right-clicking (or Control-clicking on a Mac) your card name in Eye-Fi Center and choosing to remove all items from Eye-Fi, or you can choose specific dates and delete thumbnails from there.
The requirement to upload through our servers is because of the limitations described earlier by Berend, Demetri, et al. The card can upload to our software (on one of your devices) or to our servers, but can't be programmed to support the myriad of different FTP variations out there. I don't believe it's related to the issues tellytart mentioned, though in one of those scenarios, our servers can queue the uploads until your FTP server is reachable again so I guess it's an extra benefit.
