timthumb is a great little php script that helps create thumbnail images (http://code.google.com/p/timthumb). I’ve used it before, but recently I purchased a wordpress theme that used it, and it wasn’t working.

I would get a 404 error when I tired to access the directly via a url like this:
theDomain.com/wp-content/themes/theTheme/scripts/timthumb.php?src=/wp-content/uploads/2010/05/moose1.jpg&h=207&w=237&zc=1&q=80

After some digging around in log files on my server I realized the error

SoftException in Application.cpp:610: Directory “/home/usernamehere/public_html/wp-content” is writable by others

My problem had to so with the directory permissions! “writable by others” means that the permission on the directory were set to “777”. I changed the permissions of the directory using chmod to 755, and everything started to work.

Lesson learned, if timthumb.php is not working at giving you 404 errors, check the permission of the directory that contains the php file.