RE: Don't Plagiarize Images! Here are 13 free (and Legal) ways to find high quality photos you can use on Steemit.

[wentong-syhhae]

Yes, NASA does have some spectacular photos. With a bit of imagination, some of them can even be adapted to non-science topics.
Research papers published on PubMed sometimes include unexpected treasures, Creative Commons licensed still images and even videos. Details: http://info.hsls.pitt.edu/updatereport/?p=5136
NOTE: Unfortunately, images produced by outside contractors are sometimes NOT in the public domain.