Online articles usually benefit from including a relevant image or two. A challenge is to make sure that you’re not using a copyrighted image, something that could get you into legal trouble.
You may be able to find good images through Google Images or Bing Images. Just make sure the image you’re wanting to use isn’t copyrighted by Getty or AP or some other lawyered-up organization.
I found this neat little search engine, that seems to crawl through a bunch of copyright-free image sites. Give it a try:
Here are some other image sources, which tend to include copyright-free images:
Public Domain Pictures
NASA Visible Earth
The U.S. Government
British Library Public Domain
Liam’s Pictures from Old Books