First an explanation about syncing folders instead of files. The folders in question has images that are not going to be edited and updated with the FTP server, but simply new images added to them.
Is there a way to synchronize the presence of the images on both the client on server? The client server is a Windows machine, and while some may suggest using rsync and whatnot, the server is Linux-based but it's a shared webhost so no direct access other than FTP.