Legal implementations of vectorizing copyrighted images (was Re: [Clipart] Can't submit clipart)

[Bryce Harrington]

On Wed, 6 Oct 2004, Nicu Buculei wrote:
> PS: i don't think the large-computer.svg is OK, it may be drawn from 
> scratch, but it imitates perfectly the original

Do we have some guidelines regarding what is legally allowed for
vectorizing copyrighted images?  For example, if one vectorized clipart
from a printed book, would the book's copyright still hold?  What if you
redrew them manually from scratch?  How different from the original
would it need to look?

Bryce