Copyright infringement and plagiarism are related but distinct concepts. It is possible to plagiarize even when you have cleared permission for all the copyrighted works. Similarly, it is possible to infringe copyright even when you have given careful attribution. Scholarly authors pay attention to both proper citation and copyright when writing for publication.
Per the Rackham Dissertation Handbook (PDF),
Sources that must be cited include, but are not limited to:
- language or wording either taken directly or paraphrased from another source, whether published or not;
- concepts, interpretations, techniques, methods, test instruments or procedures borrowed or adapted from another work, whether published or not;
- charts, graphs or figures borrowed or adapted from another source, whether published or not;
- photographs, films, recordings, digital material or other images from another source; and
- data, surveys or results of any kind from any other inquiry or investigation.