As with research papers, you need to give credit to information in the presentation that you found elsewhere. Make a bibliography in EasyBib of all the sources you used–whether you reference an outside source in a point you’re making, or if you borrow a photograph from someone else, put it in your bibliography. (Note: Typically, you do not need to cite clipart that you use directly from the presentation software, but check with your instructor if they require it.)
Check with your instructor to see if he or she has a preference as to how you should cite information in the presentation. If they do not have specific guidelines for you to follow, you could add a small parenthetical citation or footnote.
Either way, it’s a good idea to put a slide at the end of your presentation where you can add your EasyBib bibliography and have all your citations in one place.