HERE IS A SMALL LIST OF FREE SITES:
If you just want to host a few images, IMGUR.com is fine, but there are some contradictions of usage when using IMGUR for CODEPEN, and the Images can be removed for a breach of the Terms of service. when being used to host An Image Library for Codepen or Websites.
I think you can still use Flickr.com for Hosting, but the linking from there is a little more complex.