LR Media is a great place to find free stock photos you can use everywhere. Free for commercial use. No attribution required. Stock images can be very hard to find, especially the free stock images. However, there are plenty of other sources that host free stock photos which in most cases can be just as good. Keep in mind that many images you find still may some type of copyright.
Be sure to search the different sources for the photos license info. I have created a gallery of free stock images that are already known to be CC0 so you don’t have to worry.