I would think you wouldn't be able to import them from a thread but you can add them directly from your files.
I too had several images just added that I had originally decided not to add as I already had several better ones in the entry. Some entries have 10-30 images and I think it may be overkill to add more, especially from members who already have numerous images submitted.
You can always propose to remove an image if you really don't want it in an entry.
