How to avoid 404 for images in access log?

[etrader]

Thanks Reinis! It worked like a charm. But I have another problem (maybe
I should to start a new thread). It lists the access of my own server to
images. When someone visits an html page, an addition to this trick, a
line is added with my server IP for reading the image within the html
page. Since I just want the track of my traffic, this is useless to have
it as my server has loaded the images.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,215626,215642#msg-215642