I've been asked a few times now about using my work for other art, to be posted on other websites, and the like.
Copyright is simply the right of an artist to his original work. It's a protection against misrepresentation, not distribution.
That's why none of my works here have copyright licences. I don't believe in hampering distribution or re-use.
Anyone is free to use my works however they see fit. I don't require notification, I don't require credit, I don't require reimbursement - any of that would be nice, but it's not necessary. :D