Hi,
Not currently. The Image Gallery creates the thumbnails and web size images during the upload process when using the web page to upload. It also has naming conventions for storing the files on disk that are not user friendly for upload. Maybe someday we can add a folder where a user can drop unprocessed files by ftp and a button in the feature admin to import from the folder so it can process them. Its not something I plan to work on myself soon though as I have a huge list ahead of that.
The Folder Gallery already works well with ftp as it autogenerates the images and thumbnails. What is it that makes you not want to use Folder Gallery?
You can structure a series of folders beneth the ftp folder to be sets of "galleries" or albums and you can point different module instances to different albums within this tree of folders.
/Data/Sites/[SiteID]/FolderGalleries/ is the very root, but if you set an instance to a folder at a further depth instead of the root you can show an album or album collection per instance of the folder gallery.
Hope it helps,
Joe