From what I understand about copyright for intellectual property (IP), there is no need to file for it. It is automatically assigned to the creator. i.e. You can choose to take action against anyone who uses your images/literature without your permission. You'd have to take the person to court to get any compensation and this varies according to the 'loss' you have incurred as a result of others using your creation without your permission. Also you'd have to be able to prove ownership of that creation e.g. original copies or drafts, manuscripts, etc.
You can file for copyright/patent too, i.e. that means you go through the long process of proving your ownership first, so that in the event that someone infringes on your ownership, you can claim for damages more easily.