What is this HTTP_REFERRER “WordPress/4.1.2”

That log entry indicates the someone form that IP is requesting a image file from your site. The referrer “WordPress/4.1.2” indicates that it is probably using WP HTTP API, so the image is not just inserted in HTML (using <img> or any other HTML element) but requested server-side. Why? It can not be known with the provided information; maybe the other site is downloading the image to its own server.