Terra, those are
your maps (at least in terms of how much you can really "own" someone else's graphics, anyway). You put them together, so that counts for at least some bit of ownership.
I am always grateful for your submissions, but by no means do I have a say in what you do with any of your own stuff. If you wish to submit to or share your maps with other sites, you don't need my permission.
Exclusivity is always a nice thing, but I don't recall requiring anyone to pledge that to me or VGMaps.com.
It is nice of you to ask, though.