The following list shows both 'page' and 'image' hits for all status codes except 200 (Okay) and 304 (Not modified).
You can check the exact cause for error codes in the error logfiles on your webserver.
Status 206 (Partial Content) : 4 4 /pyleban.jpg Status 404 (Not Found Requests) : 304 284 /robots.txt 17 /hline.gif 3 /favicon.ico Status 405 (Method not allowed) : 1 1 /