U.S. Copyright Office (2019, October 30). Fair Use [Video]. YouTube. https://youtu.be/IFhF_tHrj4s
Because images are so often published without attribution, it can be especially difficult to locate their copyright holders. This can also make it difficult to cite images properly.
If you have an image you would like to use or license but need to identify and contact the copyright holder, a reverse image search engine may be helpful. You can use a reverse image search engine to find out where an image came from, where it is being used, and whether higher resolution or modified versions of the image exist.
U.S. Copyright Office. (2019, December 18). What is Public Domain? [Video]. YouTube. https://youtu.be/PMp_-OX15Jc
If the image you want to include in your work does not have a Creative Commons license or is not in the public domain, you should contact the copyright holder to get permission to use their work, especially if your work is going to be published for commercial purposes. However, if your use of the image falls under the conditions of Fair Use, you do not need to seek permission; most student work will not need permissions.