I make every effort to ensure that all of my images are primary sources and are public images. I particularly try and make every effort to ensure that I cite every image I use. As educators we are covered by Fair Use policies as far as copyright goes for the most part. But that does not, nor should it, excuse us from making efforts to cite things properly and to not abuse that which we have been permitted to do.
Therefore, I have created a list of saved websites (bookmarks) that are free, public images. These are, for the most part (probably 95%) are free of copyright.
I’ll be adding to this list as time goes on.