It is unethical, constitutes plagerism, and often violates copyright law simply to copy and image (even in another medium) that was made by someone else. So, as with any reapportiation, any work that makes use of other artists' work or published works must show substantial and significant development beyond duplication. Referencing other works of art has been done throughout the art making process. If you need to reference works, do so without plagerizing the work or artist.
