It is likely existing anatomical illustrations are often used as the basis for new illustrative works, given not all illustrators have access to human tissues, bodies, or prosections on which to base their illustrations. Potential issues arise with this practice in the realms of copyright infringement and plagiarism when authors are seeking to publish, a matter becoming more prevalent with the proliferation in publishing platforms and the increased adoption of generative artificial intelligence applications within academia. However, there is little published guidance that might inform authors when using an existing illustration as the basis for new work. This article provides information pertaining to copyright, copyright infringement, fair use and fair dealings, plagiarism, and the overlap of copyright and plagiarism to highlight issues of law and ethics that are relevant to the creation of illustrations. Interestingly, the determination of exactly what constitutes an "original" illustration per construction from a secondary source has not been determined in case law for anatomy illustrations. This fact illuminates the absence of a "bright-line" test for illustration reproduction and the difficulties in the objective assessment of what constitutes a "nonoriginal" illustration. The term "substantively different" is useful for determining whether illustrations derived from secondary sources can be deemed original. This article delivers guidance on how to develop illustrations with reference to determining whether copyright has been breached or plagiarism has occurred. It also provides information that will direct decision-making around illustrative content.