Don't steal someone else's photos or images! Morguefile has a ton of images that you can freely use for your research projects and presentation. Many of them don't require any credit : )
How to know if it's fake or true?
3 steps: Check the facts. (ie, Snopes.com; is the source professional or credible?. Follow your gut feeling. Think about it before passing on or sharing with others on social media. Click on the image for a good article on the issue.