I just changed the last thing and cleaned up the url's of all the pictures. During the past week I also changed some things to the part of the website that throttles the downloads. The part that checks the number of downloaded pages is now more precise, and I'm able to control exactly how long the lock stays on.
The duration of the lock is now 30 minutes, and the countdown starts from the moment that the number of downloaded pages per minute is under the permitted number (6 pages per minute or 10 seconds per page). So if someone keeps trying in a too fast rate, the lock stays on.
Even though I tried to throttle the search-engines by modifying robots.txt, some search-engines keep hitting the download-limit. To do that, they must download more than 5 times the allowed rate. Too bad for them, I've doubled the crawl-delay.
I also made a browser-module to be able to see who's now blocked and who has been blocked.
This is all controlled by the database and a cron-script and I'm still thinking about improvements.
Previous adjustments are paying off, the website is somewhat lighter, and certainly faster in reponse times. Probably the best change was a limit on the number of rewrite-rules in the .htaccess file.
The hits for february are up by 20%, but the web-traffic stayed the same, so I gained almost 20%. The check-script also uses an open connection to the database, so the connect time is zero and it minimizes the number of needes connections.
For now I keep looking in the referrer-lists and see the next thing I'm going to change: the downloadable sounds as someone is linking to them. Also I would like to add an list of favourite comics, based on webhits.