Did you manage to sort this out?
I've been trying for a while to find a solution but without success so maybe someone knows a trick to achieve this?
Basically, I noticed that I've got 1500 pictures under the Uploads folder, I was making back-ups regularly but yesterday I moved to a different web hosts and my surprise was that after uploading the files in the Uploads folder a lot of images were missing, so I realized that the FTP server had not been returning ALL pictures inside that folder in previous backups.
I've now seen and marked that I want the files to be organized in YYYY/MM from now on, but... is it possible to somehow organize ALL the already existing 1500 pics with the same structure? ie, like a plugin or something to move all those pics to previous years/months and update all require links?
Thanks for any tip, I don't want backups to keep failing in the future...