%e3%80%90%e8%8a%b1%e7%b2%89%e5%af%be%e7%ad%96%e3%80%91%e3%83%9d%e3%83%bc%e3%82%bf%e3%83%96%e3%83%ab%e7%a9%ba%e6%b0%97%e6%b8%85%e6%b5%84%e6%a9%9f-%e3%82%ab%e3%83%89%e3%83%bc-mp-c20u

Please don't remove that. It's just an empty symbolic file that keeps the field filled (some themes/plugins depend on having an attached file to work). But you are free to use any image you want instead of this file.