Why not just use flickr? A search for images with &quot;No known copyright restrictions&quot; returned 663,502 results.
<a href="https:&#x2F;&#x2F;www.flickr.com&#x2F;search&#x2F;?license=7%2C9%2C10&amp;text=&amp;advanced=1&amp;view_all=1" rel="nofollow">https:&#x2F;&#x2F;www.flickr.com&#x2F;search&#x2F;?license=7%2C9%2C10&amp;text=&amp;adva...</a>