You could try Pixabay. Their images are free to use, although whether you’ll find what you want, I don’t know. (Some of their links go to Shutterstock, which is a paid service, but they’re clearly marked. Just stick with the Pixabay images if you want free ones.)
There are also a number of threads - mainly in the Content category - with suggestions for free image services. Have a look around there. This is one of the most recent: