Plagiarism and copyright infringement may have some overlap, but they are discrete considerations.  Plagiarism is a form of academic dishonesty that can arise from falsely claiming the ideas and scholarship of another person as your own.  Copyright infringement is a legal concern that can arise from engaging in one of the exclusive rights of a copyright holder (copying, distributing, displaying) without permission of the copyright holder, or beyond the bounds of copyright infringement defenses such as fair use.  Citing your work appropriately may absolve you of plagiarism concerns, but citation alone does not guard against claims of copyright infringement.  For more information on the differences between copyright infringement and plagiarism, please see the LibGuide Copyright Resources to Support Publishing and Teaching, What is Plagiarism - https://guides.library.upenn.edu/copyright/plagiarism.  For support in avoiding plagiarism, please see the LibGuide Citation Practices and Avoiding Plagiarism - https://guides.library.upenn.edu/citationpractices.