A basic caching imgur mirror script in PHP
I would recommend using a script like this in your crontab to clear up old files
*/60 * * * * find ~/kageurufu.net/imgur/cache -type f -mtime +7 -delete
this will keep your cache from growing too big, if you are limited on space
put this on your web server, create a folder named "cache" (or edit the script to point elsewhere)
Set cache to be non-execute, in whatever webserver you use to prevent exploits being uploaded.
You can also put the cache outside your web directory to keep it more secure.