In addition to Google and Google Scholar, there are other resources to help you find images. The Library has created a guide to help you find images for your assignments at Queen's: Finding Images
You can also consult the guide to Resources for Finding Materials you can use on the Internet, prepared by the library's copyright specialist.
Once you have found the image, don't forget to cite it. If you don't know how, please refer to the tab "Citing Sources" in this guide.