Royalty-free, or RF, refers to the right to use copyright material or intellectual property without the need to pay royalties or license fees for each use or per volume sold, or some time period of use or sales.
The "free" in royalty-free does not mean there is no cost for the license, but instead refers to being able to freely use the image without paying additional royalties. A small-business owner, for example, may opt to pay a one-time fee for RF images for his website.
Please use images that have given consent for the general public to use. Here are two sites that have royalty free images for you to use:
https://pixabay.com/
https://www.pexels.com/
