OK, so I thought then that the Object Library would bring the icons across, but this doesn't happen either; the Image Library is still empty (in this test stack) but in Icons and Border, the icon id references are once again shown.
So my question here please: is there something which I've missed/can't find in the Rev prog to check, etc which would enable the custom images (icons) be copied over as well into the Image Library in one hit (to save having to reimport 24 images in again for 8 buttons, let's say,) or is this just the way it is?

PS Fingers crossed I won't have to use the "whoops/embarrassed/right under my nose emoticon with the answer here...!