Every Stock Photo is a search engine for public domain and Creative Commons licensed pictures. When you search on Every Stock Photo it pulls images from dozens of sources across the web. If you click on an image in your search results you will be taken to a larger version of the image, a link to the source, and the attribution requirements for using that picture.
https://www.freetech4teachers.com/2018/09/find-free-photos-by-searching-on-every.html