Any opinions on the best way to stop direct linking? I noticed in the logs a while back that more bandwidth was going to src images getting inlined in other people's forums than was being used by my image board itself. So it's time to do something.

I noticed some sites watch the HTTP Referer field while other sites watch for a cookie they give out. I guess one advantage with the latter is that it would work with web translation sites. Meanwhile the former would allow you to let blank referrers by (like for links said in chat).