free images in Google Image Search?
Answer
The basics of image copyright are covered on https://support.google.com/legal/answer/3463239?sa=X&ved=2ahUKEwi95Y3Hs_HbAhUNeawKHWEcDxYQlZ0DegQIARAB
Unfortunately, not all images found through Google Images Search are fair use…each image has its own policy.
To limit to free images use the Advanced Search page https://www.google.com/advanced_image_search
and select "free to use" on the bottom pull-down option.