Most of my stuff here is from my own artwork . Teddie helped me make sure it was marked correctly to protect it.
I occasionally use CD Art. Nearly all I use is under licence.
Rules are differerent according to Source.
I use some from Dover from samples they send via email. These I mark with their name.
Example Dover I put ©Dover And put My Tagging mark.. Teddie helped me enormously on these issues. The other thing I do Is I add the copyright after tag is complete and is the size I want. This way it remains legible. If you mark and then resize often it is no longer clear.
Maureen