Well, okay. I said I'm leaving this account, and I have, but I randomly logged in today to see that I got quite a few notes asking basically the same question, so let me set something straight.
They way I see it, the only reason to make vectors like I did, outside of personal enjoyment of course, is to provide source material for others to work with. Sometimes you see those cool show-accurate comics, wallpapers, things like that. They're often made by ponies that aren't artistically talented. So how do they achieve it? By using vectors made by those who were bored enough to produce them.
So in short - yes, you can. Anything in my gallery is a fair game for you to use in whatever it is your little pony head conceived
If I weren't too lazy, I'd go through my gallery and put this on it. But I am. So you better read this journal, since who knows if I ever log here again.