There are many resources for finding images for your project. NOTE: If this project is going anywhere but in a professor's desk drawer, you need to use public domain or open access images (most open access images these days are under a Creative Commons license), to avoid violating copyright law. You could also contact the copyright holder of the image and ask permission to use.
The New York Public Library has over 180,000 digital images that you can use for free!
Not all images on Google Images are Creative Commons licensed, but you can limit your search results to only images available under a Creative Commons license, as follows:
Click on "tools":
Then click on "usage rights". If an image has been licensed for reuse, it means you can use it - giving permission for modification means you can also make changes to it. Giving permission for noncommercial use means that it can't be used in anything that is trying to make money.