It is always a good idea to cite images, even in a PowerPoint Presentation, to give credit to the person(s) who created an image.
APA and MLA do not offer specific advice on how to cite within PowerPoint presentations, but the guidelines can be adapted to include a “Source” line at the bottom of each slide, similar to in-text citations in a paper, and a list of References or Citations at the end of the presentation
Example: Source: Author, date
Remember to always check with your professor on specific citation requirements for your course assignments.