I'm aware that the module cleans up and deletes uploaded images after all instances of preset applied images have been removed ie. when none remain attached to any nodes.

That's the situation I have except that one original uploaded image has remained, for whatever reason.

My question is; after removing the image from the file system, will simply removing that file's entry from the DB's 'file' table be acceptable given that the file is definitely not attached to any node?

Good work guys, many thanks, Bob.