Most of the images you find on a Google image search are not usable without breaking copyright. The websites below provide access to thousands of photos that you can freely use in your work. It is important to check the license of each image carefully as some will require attribution and some may not let you adapt the images as you require. It is really important to avoid copyrighted material in anything you intend to publish or share.
Don't forget - if you are using any images in written academic work or presentations, it is good academic practice to still cite your sources.
Confused by image licenses? Make sure you check our handy guide.