Here is an image reuse tool to help you know what to do.
When reusing images, it is important to provide proper attribution, including:
Figure 1. These engines should have, but couldn’t quite would have.
Chapter 12: Engines
McAuthor, John D., Microbiology and the automobile, 390-412
Copyright © 2016 by MadeUp Publisher, an imprint of Fake Images Inc.
Public domain is not owned by anyone
You can use, publish, change, etc.
Attribution is not required by you should do it anyway
Materials published by the U.S. prior to 1923 are in the Public Domain
Government Publications are in the Public Domain
Creative Commons is a type of Copyright that simplifies sharing and reuse
There are six types of CC licenses
You must attribute CC materials, and some hold greater restrictions
Attribution is Required for All
Use, Share, distribute, build upon, use commercially
SA =Share Alike
Must share anything you make under the same license
NC SA = Noncommercial, Share alike
Must share anything you make under the same license, cannot use commercially
NC = Non-Commercial
You cannot use commercially (cannot make $$)
ND = No Derivatives
Must keep licensed item whole and unchanged
NC ND = Non-Commercial, No Derivatives
Must keep licensed item unchanged & whole, cannot use commercially
More info at: https://creativecommons.org/licenses